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- Nancy Clark's Sports Nutrition Guidebook
In Nancy Clark’s Sports Nutrition Guidebook, you’ll get real-world advice from an internationally respected and trusted sports nutritionist. You’ll find the latest research and information on what to eat before, during, and after exercise; sport drinks and energy foods; popular trends like keto and gluten-free diets; when and how much carbohydrate to eat; meal patterns that fit your training schedule; sustainability; and digestive issues. You’ll learn practical tips regarding vegan, diabetic, gluten-free, low-FODMAP, and bariatric diets. You’ll also find help for athletes with anorexia and binge-eating disorders. You'll learn how to resolve confusion about what to on a daily basis so you can make healthy and informed dietary decisions for yourself and your busy family.
Clark's practical suggestions for eating on the go will help you make good choices in any restaurant, café, drive-through, or convenience store. Learn what to eat before and during exercise and events, how to refuel for optimal recovery, and what athletes need to know about relative energy deficiency in sport (RED-S). With 89 family-friendly recipes, you’ll find plenty of meals to fuel performance that you can make right in your own kitchen.
Whether you’re preparing for competition or simply fueling your active lifestyle, Nancy Clark’s Sports Nutrition Guidebook will show you how to get maximum benefit from the foods you choose and the meals you make. Why settle for your current athletic level when a good fueling program can help you perform even better?
Earn continuing education credits/units! A continuing education course and exam that uses this book is also available. It may be purchased separately or as part of a package that includes all the course materials and exam.
Chapter 1. Building a High-Energy Eating Plan
Chapter 2. Eating to Stay Healthy for the Long Run
Chapter 3. Breakfast: The Key to a Successful Sports Diet
Chapter 4. Lunch and Dinner: At Home, on the Run, and on the Road
Chapter 5. Between Meals: Snacking for Health and Sustained Energy
Chapter 6. Carbohydrate: Simplifying a Complex Topic
Chapter 7. Protein: Building and Repairing Muscles
Chapter 8. Fluids: Replacing Sweat Losses to Maintain Performance
Part II. The Science of Eating and Exercise
Chapter 9. Fueling Before Exercise
Chapter 10. Fueling During and After Exercise
Chapter 11. Supplements, Performance Enhancers, and Engineered Sports Foods
Chapter 12. Nutrition and Active Women
Chapter 13. Athlete-Specific Nutrition Advice
Part III. Balancing Weight and Activity
Chapter 14. Assessing Your Body: Fat, Fit, or Fine?
Chapter 15. Gaining Weight the Healthy Way
Chapter 16. Losing Weight Without Starving
Chapter 17. Dieting Gone Awry: Eating Disorders and Food Obsessions
Part IV. Winning Recipes for Peak Performance
Chapter 18. Breads and Breakfasts
Chapter 19. Pasta, Rice, and Potatoes
Chapter 20. Vegetables and Salads
Chapter 21. Chicken and Turkey
Chapter 22. Fish and Seafood
Chapter 23. Beef and Pork
Chapter 24. Beans and Tofu
Chapter 25. Beverages and Smoothies
Chapter 26. Snacks and Desserts
Appendix A. For More Information
Appendix B. Selected References
Nancy Clark, MS, RD, CSSD, is an internationally respected and trusted sports nutritionist specializing in nutrition for performance, wellness, and weight management, including helping athletes with eating disorders. At her private practice in the Boston area (Newton, Massachusetts), she counsels active people of all ages and athletic abilities—from high school athletes to Olympians—by giving one-on-one, personalized advice.
In the 40 years in which she has specialized in sports dietetics, Clark has helped thousands of casual and competitive athletes. Her more renowned clients have included members of the Boston Red Sox, Bruins, and Celtics, as well as athletes from many colleges in the area, including Boston College, Tufts University, and Brandeis University.
Clark enjoys speaking to teams, clubs, and health professionals, as well as writing as a way to teach people how to eat to win. Her best-selling book, Nancy Clark's Sports Nutrition Guidebook, has sold over 750,000 copies and is now in its sixth edition. Her other books include food guides for soccer players, new runners, marathoners, and cyclists. She also writes a monthly nutrition column called “The Athlete's Kitchen,” which appears regularly in over 100 sports publications and websites. Her nutrition advice and photo have even graced the back of the Wheaties box!
Clark received her undergraduate degree in nutrition from Simmons University in Boston and was honored with the Simmons Distinguished Alumna Award in 2007. Her dietetic internship was at Massachusetts General Hospital. She received her graduate degree in nutrition, with a focus on exercise physiology, from Boston University. She is a fellow of both the Academy of Nutrition and Dietetics and the American College of Sports Medicine (ACSM), and she has been a member of ACSM’s board of trustees. In 2015, she received the Nutrition Science Media Award from the American Society for Nutrition.
Carbohydrate: simplifying a complex topic
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet.
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet. I constantly study the research and remain convinced that wholesome forms of carbohydrate are the best choices for both athletes and fitness exercisers for fueling your muscles and promoting good health. In this chapter, I will explain why.
People of all ages and athletic abilities will benefit from nourishing themselves with minimally processed carbohydrate-rich fruits, vegetables, beans, legumes, and whole-grain foods, along with the right balance of protein and healthy fats. But why do some athletes insist they feel better when they stop eating bread, cereal, and pasta? Carolyn, an avid triathlete, raved about how much better she felt after having cut out carbs. I asked, “What were you eating before you made this change?” Her answer indicated the Standard American diet (SAD), with skipped meals, abundant fast foods, and more junk snacks than high-quality meals. No wonder she felt better when she started eating better.
Other reasons for feeling so much better after giving up “carbs” might relate to food sensitivities. When you cut out a lot of foods, you eliminate the one or two items that might create feelings of unwellness. A registered dietitian can help you reach the same level of feeling great by working with you to figure out which foods contribute to the sensitivity.
Some athletes embrace a carb-free diet as a way to curb sugar binges that lead to eating too many carbs. An easier way to reduce carb binges is to prevent extreme hunger. Despite popular belief, carb binges are unlikely caused by being addicted to carbs, but rather caused by the physiological effects of hunger. Refer to chapters 5 (sweet cravings) and 16 (weight management).
The purpose of this chapter is to eliminate this confusion so you can make choices that best promote good health, appropriate weight, and optimal sports performance.
Simple and Complex Carbohydrates
The carbohydrate family includes both simple and complex carbohydrates. The simple carbohydrates are monosaccharides and disaccharides (single- and double-sugar molecules). Glucose, fructose, and galactose are monosaccharides, the simplest sugars, and can be symbolized like this:
The disaccharides can be symbolized like this:
Four common sources of disaccharides are table sugar (sucrose), milk sugar (lactose, a combination of glucose and galactose), corn syrup, and honey.
Table sugar, corn syrup, and honey all contain glucose and fructose but in different amounts.
- Table sugar, upon digestion, breaks apart into 50 percent glucose and 50 percent fructose.
- High-fructose corn syrup (HFCS), commonly used in soft drinks, breaks down to about 55 percent fructose and 45 percent glucose. (HFCS is made using chemical processes that first convert cornstarch to corn syrup and then convert about 55 percent of the glucose in the corn syrup to fructose to make it taste sweeter.)
- Honey contains about 31 percent glucose, 38 percent fructose, 10 percent other sugars, 17 percent water, and 4 percent miscellaneous particles.
Your body eventually converts all monosaccharides and disaccharides to glucose, which travels in the blood (blood glucose) to fuel your muscles and brain.
Fruits and vegetables offer a variety of sugars in differing proportions. Because you absorb different sugars at different rates and by differing pathways, research indicates that consuming a variety of sugars allows for better absorption during exercise. This means that you should read the ingredient label on your sports drink to be sure it offers more than one type of sugar.
Honey has been mistakenly described as being superior to HFCS or refined white sugar. If you prefer honey because of the pleasant taste, fine. But it's not superior in terms of vitamins or performance. Sugar in any form—honey, maple syrup, corn syrup, brown sugar, raw sugar, or agave—offers insignificant nutritional value, and your body digests any type of sugar or carbohydrate into glucose before using it for fuel.
Another type of sugar that is found in many engineered sports foods is maltodextrins, also called glucose polymers. Maltodextrins are chains of about five glucose molecules. Sports drinks sweetened with maltodextrins can provide energy with rapid absorption and less sweetness than regular sugar provides. Sports fuels that use maltodextrins include Hammer Nutrition products.
Complex carbohydrates, such as starch in plant foods and glycogen in muscles, are formed when sugars link together to form long complex chains, similar to a string of hundreds of pearls. They can be symbolized like this:
Plants store extra sugar in the form of starch. For example, corn is sweet when it's young, but it becomes starchy as it gets older. Its extra sugar converts into starch. In contrast to corn and other vegetables, fruits tend to convert starch into sugar as they ripen. A good example is the banana:
- A green banana with some yellow is 80 percent starch and 7 percent sugar.
- A mostly yellow banana is 25 percent starch and 65 percent sugar.
- A spotted and speckled banana is 5 percent starch and 90 percent sugar.
The potatoes, rice, bread, and other starches you eat are digested into glucose and then burned for energy or stored for future use. Humans store extra glucose mostly in the form of muscle glycogen and liver glycogen (but generally not as body fat). This glycogen is readily available for energy during exercise.
Sugars and starches have similar abilities to fuel muscles but different abilities to nourish them with vitamins and minerals:
- The refined carbohydrate in sugary soft drinks provides energy but no vitamins or minerals.
- The highly processed carbohydrate in sports drinks, candies, and gels provides energy but no vitamins or minerals, unless the foods are fortified.
- The natural sugars and unrefined carbohydrate in fruits, vegetables, and whole grains provide energy, vitamins, minerals, fiber, and phytochemicals—the fuel and spark plugs that your body's engine needs to function best.
Protein and the vegetarian
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods.
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods. They may find animal protein hard to digest or believe it is bad for their health, unethical to eat, or erosive to the environment. (Cattle are a source of greenhouse gas that contributes to global warming.) Meatless Mondays (and other days, too) are a good idea for the planet! And a balanced vegetarian diet is indeed a good investment in good health. A plant-based diet tends to have more fiber, less saturated fat, and more phytochemicals—active compounds that bolster the immune system, reduce inflammation, and are health protective.
The trick to eating a balanced vegetarian diet is to make the effort to replace meat with plant proteins. That is, if you eliminate the meatballs from your pasta dinner, add an alternative source of plant-based protein. Do not simply fuel up only on pasta and neglect your protein needs. You can get adequate protein to support your sports program by including kidney beans, chickpeas, hummus, nut butter, tofu, nuts, veggie burgers, edamame, and other forms of plant protein in each meal.
Tofu (soybean curd) and other soy products, such as soy burgers and soy milk, are smart additions to a meat-free diet. They contain a source of high-quality protein that is similar in value to animal protein. Note that a Boca Burger (soy protein) has far less protein than a hamburger, however (refer to table 7.2). Despite popular belief among male athletes, the plant estrogens in soy do not have a feminizing effect, do not reduce testosterone levels, and do not impair fertility (Messina 2010). All athletes can enjoy soy foods in moderation, as with any food, as a health-promoting part of a balanced sports diet.
For lacto-vegetarians (who consume dairy foods), milk and (Greek) yogurt are simple ways to add extra high-quality protein to meals and snacks. Although they have been given a bad rap because they are high in saturated fat, recent studies question whether a connection exits between dairy fat and heart disease and stroke regardless of the milk fat levels (de Oliveira Otto et al. 2018). This controversial topic is worthy of continued research, so until the American Heart Association gives the green light for full-fat dairy foods, a wise plan is to choose mostly reduced-fat dairy foods and balance full-fat choices into an overall healthy eating pattern. That said, blue cheese and other “moldy cheeses” may be a positive addition to the diet regardless of their saturated fat: They support gut bacteria that promote good health (Petyaev and Bashmakov 2012).
Milk, other dairy foods, eggs, and all animal sources of protein contain all the essential amino acids and are often referred to as complete proteins. The protein in soy foods such as tofu, tempeh, edamame, and soy milk are also complete proteins. The protein in rice, beans, pasta, lentils, nuts, fruits, vegetables, and other plant foods are incomplete because they contain low levels of some of the essential amino acids. Therefore, vegetarians must eat a variety of foods to get a variety of amino acids that combine with incomplete proteins to make them complete. Vegetarians who drink milk can easily do this by adding soy milk or dairy products to each meal, for example, combining (soy) milk with oatmeal or sprinkling grated low-fat (soy) cheese on beans. Note that rice and almond milks are not nutritionally equal to soy milk, but rather are very poor protein sources (see chapter 1).
Vegans (strict vegetarians who eat no dairy, eggs, or animal protein) need to consistently eat a variety of foods to optimize their intake of a variety of amino acids over the course of the day. The following combinations work particularly well together; they complement each other by boosting the limiting amino acid:
- Grains plus beans or legumes, such as rice and beans, bread and split-pea soup, tofu and brown rice, corn bread and chili with kidney beans
- Legumes plus seeds, such as chickpeas and tahini (as in hummus), tofu and sesame seeds
- Added soy products (or dairy, if nonvegan), such as cereal and (soy) milk, baked potato and Greek or soy yogurt, hummus wrap with low-fat (soy) cheese
By following these guidelines, vegetarian athletes can consume an adequate amount of complete protein every day. They may, however, lack iron and zinc, minerals found primarily in meats and other animal products. Vegans also need to be sure they get adequate riboflavin, calcium, and vitamin B12, either through a supplement or from carefully selected food sources.
Why carbohydrates are important for active people
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again.
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again. They are not fattening, and you need them to fuel your muscles so that you can enjoy your exercise program.
The average 150-pound (68 kg) man has about 1,800 calories of carbohydrate stored in the liver, muscles, blood, and body fluids in approximately the distribution shown in table 6.2.
The carbohydrate in the muscles is used during exercise. The carbohydrate in the liver is released into the bloodstream to maintain a normal blood glucose level and feed the brain (as well as the muscles). These limited carbohydrate stores influence how long you can enjoy exercising. When your glycogen stores get too low, you hit the wall—that is, you feel overwhelmingly fatigued and yearn to quit. In a research study, cyclists with depleted muscle glycogen stores were able to exercise only 55 minutes to fatigue (as measured by an inability to maintain a specified pedaling speed on a stationary bicycle), as compared with more than twice as long—about 120 minutes—when they were carbohydrate loaded (Green et al. 2007). Food works!
In comparison to the approximately 1,800 calories of stored carbohydrate, the average lean 150-pound (68 kg) man also has 60,000 to 100,000 calories of stored fat—enough to run hundreds of miles. During low-level exercise such as walking, the muscles burn primarily fat for energy. During light to moderate aerobic exercise, such as jogging, stored fat provides 50 to 60 percent of the fuel. When you exercise hard, as in sprinting, racing, lifting weights, or other intense exercise, you rely primarily on glycogen stores. Unfortunately, for competitive athletes, fat cannot be used exclusively as fuel because the muscles need a certain amount of carbohydrate to function well at high intensities, such as a surge up a hill or a sprint to the finish. Fitness exercisers can get away with a lower carbohydrate intake than elite athletes who push themselves to exhaustion can.
Biochemical changes that occur during training influence the amount of glycogen you can store in your muscles. The figures that follow indicate that well-trained muscles store 20 to 50 percent more glycogen than untrained muscles do (Costill et al. 1981; Sherman et al. 1981). This change enhances endurance capacity and is one reason a novice runner can't just load up on carbohydrate and run a top-quality marathon (table 6.3).
Because of the unfounded fears that carbohydrate is fattening or the belief that you need a high-protein diet to build muscle or a high-fat diet for endurance, many athletes today are skimping on carbohydrate foods. Some go on the paleo diet or keto diet; others go gluten free. The resulting low-carbohydrate intake can potentially hurt performance; it contrasts sharply with the diet of 2.5 to 4.5 grams of carbohydrate per pound of body weight (5 to 10 g/kg)—or 55 to 65 percent carbohydrate—recommended by most exercise and health professionals for people who train for one to three hours a day.
A case in point is ice hockey, an incredibly intense sport that relies on both muscular strength and power. During a game, carbohydrate is the primary fuel, and muscle carbohydrate (glycogen) stores decline between 38 and 88 percent. Muscle glycogen depletion relates closely to muscular fatigue. A motion analysis of elite ice hockey teams showed that the players with a high-carbohydrate (60 percent) diet skated not only 30 percent more distance but also faster than the players who ate their standard low-carbohydrate (40 percent) diet. In the final period of the game, which often determines whether a team wins or loses, the high-carbohydrate group skated 11 percent more distance than they did in the first period; the low-carbohydrate group skated 14 percent less. The researchers reached the following conclusions (Ackermark et al. 1996):
- Low muscle glycogen stores at the start of the game can jeopardize performance at the end of the game.
- Three days between games (with training on two of those days) plus a low-carbohydrate (40 percent) diet does not replace normal muscle glycogen stores (the players in the high-carbohydrate group had 45 percent more glycogen).
- The differences in performance between the well-fueled players and those who ate inadequate carbohydrate were most evident in the last period of the game.
Whether your sport is ice hockey, soccer, rugby, football, basketball, or any intense sport, remember to eat responsibly. Make carbohydrate the foundation of each meal and protein the accompaniment.
After exercise, it is important to consume carbohydrate to replenish muscle glycogen stores. In a landmark study, exercise physiologist J. Bergstrom and his colleagues (1967) compared the rate at which muscle glycogen was replaced in subjects who exercised to exhaustion and then ate either a high-protein, high-fat diet, or a high-carbohydrate diet. The subjects on the high-protein, high-fat diet (similar to an Atkins or other high-protein, low-carbohydrate diet with abundant eggs, chicken, beef, cheese, and nuts) remained glycogen depleted for five days (figure 6.1). The subjects on the high-carbohydrate diet totally replenished their muscle glycogen in two days. This result shows that protein and fat aren't stored as muscle glycogen and that carbohydrate is important for replacing depleted glycogen stores. Other research suggests that three sets of biceps curls (8 to 10 repetitions per set) reduce muscle glycogen by 35 percent (Martin, Armstrong, and Rodriquez 2005). With repeated days of low carbohydrate and high repetitions, the muscles of bodybuilders and marathon runners can soon become depleted. Hence, every athlete should eat meals in which two-thirds of the plate is dedicated to wholesome carbohydrates (grains, vegetables, fruits) and one-third to protein.
Carbohydrate: simplifying a complex topic
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet.
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet. I constantly study the research and remain convinced that wholesome forms of carbohydrate are the best choices for both athletes and fitness exercisers for fueling your muscles and promoting good health. In this chapter, I will explain why.
People of all ages and athletic abilities will benefit from nourishing themselves with minimally processed carbohydrate-rich fruits, vegetables, beans, legumes, and whole-grain foods, along with the right balance of protein and healthy fats. But why do some athletes insist they feel better when they stop eating bread, cereal, and pasta? Carolyn, an avid triathlete, raved about how much better she felt after having cut out carbs. I asked, “What were you eating before you made this change?” Her answer indicated the Standard American diet (SAD), with skipped meals, abundant fast foods, and more junk snacks than high-quality meals. No wonder she felt better when she started eating better.
Other reasons for feeling so much better after giving up “carbs” might relate to food sensitivities. When you cut out a lot of foods, you eliminate the one or two items that might create feelings of unwellness. A registered dietitian can help you reach the same level of feeling great by working with you to figure out which foods contribute to the sensitivity.
Some athletes embrace a carb-free diet as a way to curb sugar binges that lead to eating too many carbs. An easier way to reduce carb binges is to prevent extreme hunger. Despite popular belief, carb binges are unlikely caused by being addicted to carbs, but rather caused by the physiological effects of hunger. Refer to chapters 5 (sweet cravings) and 16 (weight management).
The purpose of this chapter is to eliminate this confusion so you can make choices that best promote good health, appropriate weight, and optimal sports performance.
Simple and Complex Carbohydrates
The carbohydrate family includes both simple and complex carbohydrates. The simple carbohydrates are monosaccharides and disaccharides (single- and double-sugar molecules). Glucose, fructose, and galactose are monosaccharides, the simplest sugars, and can be symbolized like this:
The disaccharides can be symbolized like this:
Four common sources of disaccharides are table sugar (sucrose), milk sugar (lactose, a combination of glucose and galactose), corn syrup, and honey.
Table sugar, corn syrup, and honey all contain glucose and fructose but in different amounts.
- Table sugar, upon digestion, breaks apart into 50 percent glucose and 50 percent fructose.
- High-fructose corn syrup (HFCS), commonly used in soft drinks, breaks down to about 55 percent fructose and 45 percent glucose. (HFCS is made using chemical processes that first convert cornstarch to corn syrup and then convert about 55 percent of the glucose in the corn syrup to fructose to make it taste sweeter.)
- Honey contains about 31 percent glucose, 38 percent fructose, 10 percent other sugars, 17 percent water, and 4 percent miscellaneous particles.
Your body eventually converts all monosaccharides and disaccharides to glucose, which travels in the blood (blood glucose) to fuel your muscles and brain.
Fruits and vegetables offer a variety of sugars in differing proportions. Because you absorb different sugars at different rates and by differing pathways, research indicates that consuming a variety of sugars allows for better absorption during exercise. This means that you should read the ingredient label on your sports drink to be sure it offers more than one type of sugar.
Honey has been mistakenly described as being superior to HFCS or refined white sugar. If you prefer honey because of the pleasant taste, fine. But it's not superior in terms of vitamins or performance. Sugar in any form—honey, maple syrup, corn syrup, brown sugar, raw sugar, or agave—offers insignificant nutritional value, and your body digests any type of sugar or carbohydrate into glucose before using it for fuel.
Another type of sugar that is found in many engineered sports foods is maltodextrins, also called glucose polymers. Maltodextrins are chains of about five glucose molecules. Sports drinks sweetened with maltodextrins can provide energy with rapid absorption and less sweetness than regular sugar provides. Sports fuels that use maltodextrins include Hammer Nutrition products.
Complex carbohydrates, such as starch in plant foods and glycogen in muscles, are formed when sugars link together to form long complex chains, similar to a string of hundreds of pearls. They can be symbolized like this:
Plants store extra sugar in the form of starch. For example, corn is sweet when it's young, but it becomes starchy as it gets older. Its extra sugar converts into starch. In contrast to corn and other vegetables, fruits tend to convert starch into sugar as they ripen. A good example is the banana:
- A green banana with some yellow is 80 percent starch and 7 percent sugar.
- A mostly yellow banana is 25 percent starch and 65 percent sugar.
- A spotted and speckled banana is 5 percent starch and 90 percent sugar.
The potatoes, rice, bread, and other starches you eat are digested into glucose and then burned for energy or stored for future use. Humans store extra glucose mostly in the form of muscle glycogen and liver glycogen (but generally not as body fat). This glycogen is readily available for energy during exercise.
Sugars and starches have similar abilities to fuel muscles but different abilities to nourish them with vitamins and minerals:
- The refined carbohydrate in sugary soft drinks provides energy but no vitamins or minerals.
- The highly processed carbohydrate in sports drinks, candies, and gels provides energy but no vitamins or minerals, unless the foods are fortified.
- The natural sugars and unrefined carbohydrate in fruits, vegetables, and whole grains provide energy, vitamins, minerals, fiber, and phytochemicals—the fuel and spark plugs that your body's engine needs to function best.
Protein and the vegetarian
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods.
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods. They may find animal protein hard to digest or believe it is bad for their health, unethical to eat, or erosive to the environment. (Cattle are a source of greenhouse gas that contributes to global warming.) Meatless Mondays (and other days, too) are a good idea for the planet! And a balanced vegetarian diet is indeed a good investment in good health. A plant-based diet tends to have more fiber, less saturated fat, and more phytochemicals—active compounds that bolster the immune system, reduce inflammation, and are health protective.
The trick to eating a balanced vegetarian diet is to make the effort to replace meat with plant proteins. That is, if you eliminate the meatballs from your pasta dinner, add an alternative source of plant-based protein. Do not simply fuel up only on pasta and neglect your protein needs. You can get adequate protein to support your sports program by including kidney beans, chickpeas, hummus, nut butter, tofu, nuts, veggie burgers, edamame, and other forms of plant protein in each meal.
Tofu (soybean curd) and other soy products, such as soy burgers and soy milk, are smart additions to a meat-free diet. They contain a source of high-quality protein that is similar in value to animal protein. Note that a Boca Burger (soy protein) has far less protein than a hamburger, however (refer to table 7.2). Despite popular belief among male athletes, the plant estrogens in soy do not have a feminizing effect, do not reduce testosterone levels, and do not impair fertility (Messina 2010). All athletes can enjoy soy foods in moderation, as with any food, as a health-promoting part of a balanced sports diet.
For lacto-vegetarians (who consume dairy foods), milk and (Greek) yogurt are simple ways to add extra high-quality protein to meals and snacks. Although they have been given a bad rap because they are high in saturated fat, recent studies question whether a connection exits between dairy fat and heart disease and stroke regardless of the milk fat levels (de Oliveira Otto et al. 2018). This controversial topic is worthy of continued research, so until the American Heart Association gives the green light for full-fat dairy foods, a wise plan is to choose mostly reduced-fat dairy foods and balance full-fat choices into an overall healthy eating pattern. That said, blue cheese and other “moldy cheeses” may be a positive addition to the diet regardless of their saturated fat: They support gut bacteria that promote good health (Petyaev and Bashmakov 2012).
Milk, other dairy foods, eggs, and all animal sources of protein contain all the essential amino acids and are often referred to as complete proteins. The protein in soy foods such as tofu, tempeh, edamame, and soy milk are also complete proteins. The protein in rice, beans, pasta, lentils, nuts, fruits, vegetables, and other plant foods are incomplete because they contain low levels of some of the essential amino acids. Therefore, vegetarians must eat a variety of foods to get a variety of amino acids that combine with incomplete proteins to make them complete. Vegetarians who drink milk can easily do this by adding soy milk or dairy products to each meal, for example, combining (soy) milk with oatmeal or sprinkling grated low-fat (soy) cheese on beans. Note that rice and almond milks are not nutritionally equal to soy milk, but rather are very poor protein sources (see chapter 1).
Vegans (strict vegetarians who eat no dairy, eggs, or animal protein) need to consistently eat a variety of foods to optimize their intake of a variety of amino acids over the course of the day. The following combinations work particularly well together; they complement each other by boosting the limiting amino acid:
- Grains plus beans or legumes, such as rice and beans, bread and split-pea soup, tofu and brown rice, corn bread and chili with kidney beans
- Legumes plus seeds, such as chickpeas and tahini (as in hummus), tofu and sesame seeds
- Added soy products (or dairy, if nonvegan), such as cereal and (soy) milk, baked potato and Greek or soy yogurt, hummus wrap with low-fat (soy) cheese
By following these guidelines, vegetarian athletes can consume an adequate amount of complete protein every day. They may, however, lack iron and zinc, minerals found primarily in meats and other animal products. Vegans also need to be sure they get adequate riboflavin, calcium, and vitamin B12, either through a supplement or from carefully selected food sources.
Why carbohydrates are important for active people
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again.
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again. They are not fattening, and you need them to fuel your muscles so that you can enjoy your exercise program.
The average 150-pound (68 kg) man has about 1,800 calories of carbohydrate stored in the liver, muscles, blood, and body fluids in approximately the distribution shown in table 6.2.
The carbohydrate in the muscles is used during exercise. The carbohydrate in the liver is released into the bloodstream to maintain a normal blood glucose level and feed the brain (as well as the muscles). These limited carbohydrate stores influence how long you can enjoy exercising. When your glycogen stores get too low, you hit the wall—that is, you feel overwhelmingly fatigued and yearn to quit. In a research study, cyclists with depleted muscle glycogen stores were able to exercise only 55 minutes to fatigue (as measured by an inability to maintain a specified pedaling speed on a stationary bicycle), as compared with more than twice as long—about 120 minutes—when they were carbohydrate loaded (Green et al. 2007). Food works!
In comparison to the approximately 1,800 calories of stored carbohydrate, the average lean 150-pound (68 kg) man also has 60,000 to 100,000 calories of stored fat—enough to run hundreds of miles. During low-level exercise such as walking, the muscles burn primarily fat for energy. During light to moderate aerobic exercise, such as jogging, stored fat provides 50 to 60 percent of the fuel. When you exercise hard, as in sprinting, racing, lifting weights, or other intense exercise, you rely primarily on glycogen stores. Unfortunately, for competitive athletes, fat cannot be used exclusively as fuel because the muscles need a certain amount of carbohydrate to function well at high intensities, such as a surge up a hill or a sprint to the finish. Fitness exercisers can get away with a lower carbohydrate intake than elite athletes who push themselves to exhaustion can.
Biochemical changes that occur during training influence the amount of glycogen you can store in your muscles. The figures that follow indicate that well-trained muscles store 20 to 50 percent more glycogen than untrained muscles do (Costill et al. 1981; Sherman et al. 1981). This change enhances endurance capacity and is one reason a novice runner can't just load up on carbohydrate and run a top-quality marathon (table 6.3).
Because of the unfounded fears that carbohydrate is fattening or the belief that you need a high-protein diet to build muscle or a high-fat diet for endurance, many athletes today are skimping on carbohydrate foods. Some go on the paleo diet or keto diet; others go gluten free. The resulting low-carbohydrate intake can potentially hurt performance; it contrasts sharply with the diet of 2.5 to 4.5 grams of carbohydrate per pound of body weight (5 to 10 g/kg)—or 55 to 65 percent carbohydrate—recommended by most exercise and health professionals for people who train for one to three hours a day.
A case in point is ice hockey, an incredibly intense sport that relies on both muscular strength and power. During a game, carbohydrate is the primary fuel, and muscle carbohydrate (glycogen) stores decline between 38 and 88 percent. Muscle glycogen depletion relates closely to muscular fatigue. A motion analysis of elite ice hockey teams showed that the players with a high-carbohydrate (60 percent) diet skated not only 30 percent more distance but also faster than the players who ate their standard low-carbohydrate (40 percent) diet. In the final period of the game, which often determines whether a team wins or loses, the high-carbohydrate group skated 11 percent more distance than they did in the first period; the low-carbohydrate group skated 14 percent less. The researchers reached the following conclusions (Ackermark et al. 1996):
- Low muscle glycogen stores at the start of the game can jeopardize performance at the end of the game.
- Three days between games (with training on two of those days) plus a low-carbohydrate (40 percent) diet does not replace normal muscle glycogen stores (the players in the high-carbohydrate group had 45 percent more glycogen).
- The differences in performance between the well-fueled players and those who ate inadequate carbohydrate were most evident in the last period of the game.
Whether your sport is ice hockey, soccer, rugby, football, basketball, or any intense sport, remember to eat responsibly. Make carbohydrate the foundation of each meal and protein the accompaniment.
After exercise, it is important to consume carbohydrate to replenish muscle glycogen stores. In a landmark study, exercise physiologist J. Bergstrom and his colleagues (1967) compared the rate at which muscle glycogen was replaced in subjects who exercised to exhaustion and then ate either a high-protein, high-fat diet, or a high-carbohydrate diet. The subjects on the high-protein, high-fat diet (similar to an Atkins or other high-protein, low-carbohydrate diet with abundant eggs, chicken, beef, cheese, and nuts) remained glycogen depleted for five days (figure 6.1). The subjects on the high-carbohydrate diet totally replenished their muscle glycogen in two days. This result shows that protein and fat aren't stored as muscle glycogen and that carbohydrate is important for replacing depleted glycogen stores. Other research suggests that three sets of biceps curls (8 to 10 repetitions per set) reduce muscle glycogen by 35 percent (Martin, Armstrong, and Rodriquez 2005). With repeated days of low carbohydrate and high repetitions, the muscles of bodybuilders and marathon runners can soon become depleted. Hence, every athlete should eat meals in which two-thirds of the plate is dedicated to wholesome carbohydrates (grains, vegetables, fruits) and one-third to protein.
Carbohydrate: simplifying a complex topic
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet.
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet. I constantly study the research and remain convinced that wholesome forms of carbohydrate are the best choices for both athletes and fitness exercisers for fueling your muscles and promoting good health. In this chapter, I will explain why.
People of all ages and athletic abilities will benefit from nourishing themselves with minimally processed carbohydrate-rich fruits, vegetables, beans, legumes, and whole-grain foods, along with the right balance of protein and healthy fats. But why do some athletes insist they feel better when they stop eating bread, cereal, and pasta? Carolyn, an avid triathlete, raved about how much better she felt after having cut out carbs. I asked, “What were you eating before you made this change?” Her answer indicated the Standard American diet (SAD), with skipped meals, abundant fast foods, and more junk snacks than high-quality meals. No wonder she felt better when she started eating better.
Other reasons for feeling so much better after giving up “carbs” might relate to food sensitivities. When you cut out a lot of foods, you eliminate the one or two items that might create feelings of unwellness. A registered dietitian can help you reach the same level of feeling great by working with you to figure out which foods contribute to the sensitivity.
Some athletes embrace a carb-free diet as a way to curb sugar binges that lead to eating too many carbs. An easier way to reduce carb binges is to prevent extreme hunger. Despite popular belief, carb binges are unlikely caused by being addicted to carbs, but rather caused by the physiological effects of hunger. Refer to chapters 5 (sweet cravings) and 16 (weight management).
The purpose of this chapter is to eliminate this confusion so you can make choices that best promote good health, appropriate weight, and optimal sports performance.
Simple and Complex Carbohydrates
The carbohydrate family includes both simple and complex carbohydrates. The simple carbohydrates are monosaccharides and disaccharides (single- and double-sugar molecules). Glucose, fructose, and galactose are monosaccharides, the simplest sugars, and can be symbolized like this:
The disaccharides can be symbolized like this:
Four common sources of disaccharides are table sugar (sucrose), milk sugar (lactose, a combination of glucose and galactose), corn syrup, and honey.
Table sugar, corn syrup, and honey all contain glucose and fructose but in different amounts.
- Table sugar, upon digestion, breaks apart into 50 percent glucose and 50 percent fructose.
- High-fructose corn syrup (HFCS), commonly used in soft drinks, breaks down to about 55 percent fructose and 45 percent glucose. (HFCS is made using chemical processes that first convert cornstarch to corn syrup and then convert about 55 percent of the glucose in the corn syrup to fructose to make it taste sweeter.)
- Honey contains about 31 percent glucose, 38 percent fructose, 10 percent other sugars, 17 percent water, and 4 percent miscellaneous particles.
Your body eventually converts all monosaccharides and disaccharides to glucose, which travels in the blood (blood glucose) to fuel your muscles and brain.
Fruits and vegetables offer a variety of sugars in differing proportions. Because you absorb different sugars at different rates and by differing pathways, research indicates that consuming a variety of sugars allows for better absorption during exercise. This means that you should read the ingredient label on your sports drink to be sure it offers more than one type of sugar.
Honey has been mistakenly described as being superior to HFCS or refined white sugar. If you prefer honey because of the pleasant taste, fine. But it's not superior in terms of vitamins or performance. Sugar in any form—honey, maple syrup, corn syrup, brown sugar, raw sugar, or agave—offers insignificant nutritional value, and your body digests any type of sugar or carbohydrate into glucose before using it for fuel.
Another type of sugar that is found in many engineered sports foods is maltodextrins, also called glucose polymers. Maltodextrins are chains of about five glucose molecules. Sports drinks sweetened with maltodextrins can provide energy with rapid absorption and less sweetness than regular sugar provides. Sports fuels that use maltodextrins include Hammer Nutrition products.
Complex carbohydrates, such as starch in plant foods and glycogen in muscles, are formed when sugars link together to form long complex chains, similar to a string of hundreds of pearls. They can be symbolized like this:
Plants store extra sugar in the form of starch. For example, corn is sweet when it's young, but it becomes starchy as it gets older. Its extra sugar converts into starch. In contrast to corn and other vegetables, fruits tend to convert starch into sugar as they ripen. A good example is the banana:
- A green banana with some yellow is 80 percent starch and 7 percent sugar.
- A mostly yellow banana is 25 percent starch and 65 percent sugar.
- A spotted and speckled banana is 5 percent starch and 90 percent sugar.
The potatoes, rice, bread, and other starches you eat are digested into glucose and then burned for energy or stored for future use. Humans store extra glucose mostly in the form of muscle glycogen and liver glycogen (but generally not as body fat). This glycogen is readily available for energy during exercise.
Sugars and starches have similar abilities to fuel muscles but different abilities to nourish them with vitamins and minerals:
- The refined carbohydrate in sugary soft drinks provides energy but no vitamins or minerals.
- The highly processed carbohydrate in sports drinks, candies, and gels provides energy but no vitamins or minerals, unless the foods are fortified.
- The natural sugars and unrefined carbohydrate in fruits, vegetables, and whole grains provide energy, vitamins, minerals, fiber, and phytochemicals—the fuel and spark plugs that your body's engine needs to function best.
Protein and the vegetarian
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods.
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods. They may find animal protein hard to digest or believe it is bad for their health, unethical to eat, or erosive to the environment. (Cattle are a source of greenhouse gas that contributes to global warming.) Meatless Mondays (and other days, too) are a good idea for the planet! And a balanced vegetarian diet is indeed a good investment in good health. A plant-based diet tends to have more fiber, less saturated fat, and more phytochemicals—active compounds that bolster the immune system, reduce inflammation, and are health protective.
The trick to eating a balanced vegetarian diet is to make the effort to replace meat with plant proteins. That is, if you eliminate the meatballs from your pasta dinner, add an alternative source of plant-based protein. Do not simply fuel up only on pasta and neglect your protein needs. You can get adequate protein to support your sports program by including kidney beans, chickpeas, hummus, nut butter, tofu, nuts, veggie burgers, edamame, and other forms of plant protein in each meal.
Tofu (soybean curd) and other soy products, such as soy burgers and soy milk, are smart additions to a meat-free diet. They contain a source of high-quality protein that is similar in value to animal protein. Note that a Boca Burger (soy protein) has far less protein than a hamburger, however (refer to table 7.2). Despite popular belief among male athletes, the plant estrogens in soy do not have a feminizing effect, do not reduce testosterone levels, and do not impair fertility (Messina 2010). All athletes can enjoy soy foods in moderation, as with any food, as a health-promoting part of a balanced sports diet.
For lacto-vegetarians (who consume dairy foods), milk and (Greek) yogurt are simple ways to add extra high-quality protein to meals and snacks. Although they have been given a bad rap because they are high in saturated fat, recent studies question whether a connection exits between dairy fat and heart disease and stroke regardless of the milk fat levels (de Oliveira Otto et al. 2018). This controversial topic is worthy of continued research, so until the American Heart Association gives the green light for full-fat dairy foods, a wise plan is to choose mostly reduced-fat dairy foods and balance full-fat choices into an overall healthy eating pattern. That said, blue cheese and other “moldy cheeses” may be a positive addition to the diet regardless of their saturated fat: They support gut bacteria that promote good health (Petyaev and Bashmakov 2012).
Milk, other dairy foods, eggs, and all animal sources of protein contain all the essential amino acids and are often referred to as complete proteins. The protein in soy foods such as tofu, tempeh, edamame, and soy milk are also complete proteins. The protein in rice, beans, pasta, lentils, nuts, fruits, vegetables, and other plant foods are incomplete because they contain low levels of some of the essential amino acids. Therefore, vegetarians must eat a variety of foods to get a variety of amino acids that combine with incomplete proteins to make them complete. Vegetarians who drink milk can easily do this by adding soy milk or dairy products to each meal, for example, combining (soy) milk with oatmeal or sprinkling grated low-fat (soy) cheese on beans. Note that rice and almond milks are not nutritionally equal to soy milk, but rather are very poor protein sources (see chapter 1).
Vegans (strict vegetarians who eat no dairy, eggs, or animal protein) need to consistently eat a variety of foods to optimize their intake of a variety of amino acids over the course of the day. The following combinations work particularly well together; they complement each other by boosting the limiting amino acid:
- Grains plus beans or legumes, such as rice and beans, bread and split-pea soup, tofu and brown rice, corn bread and chili with kidney beans
- Legumes plus seeds, such as chickpeas and tahini (as in hummus), tofu and sesame seeds
- Added soy products (or dairy, if nonvegan), such as cereal and (soy) milk, baked potato and Greek or soy yogurt, hummus wrap with low-fat (soy) cheese
By following these guidelines, vegetarian athletes can consume an adequate amount of complete protein every day. They may, however, lack iron and zinc, minerals found primarily in meats and other animal products. Vegans also need to be sure they get adequate riboflavin, calcium, and vitamin B12, either through a supplement or from carefully selected food sources.
Why carbohydrates are important for active people
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again.
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again. They are not fattening, and you need them to fuel your muscles so that you can enjoy your exercise program.
The average 150-pound (68 kg) man has about 1,800 calories of carbohydrate stored in the liver, muscles, blood, and body fluids in approximately the distribution shown in table 6.2.
The carbohydrate in the muscles is used during exercise. The carbohydrate in the liver is released into the bloodstream to maintain a normal blood glucose level and feed the brain (as well as the muscles). These limited carbohydrate stores influence how long you can enjoy exercising. When your glycogen stores get too low, you hit the wall—that is, you feel overwhelmingly fatigued and yearn to quit. In a research study, cyclists with depleted muscle glycogen stores were able to exercise only 55 minutes to fatigue (as measured by an inability to maintain a specified pedaling speed on a stationary bicycle), as compared with more than twice as long—about 120 minutes—when they were carbohydrate loaded (Green et al. 2007). Food works!
In comparison to the approximately 1,800 calories of stored carbohydrate, the average lean 150-pound (68 kg) man also has 60,000 to 100,000 calories of stored fat—enough to run hundreds of miles. During low-level exercise such as walking, the muscles burn primarily fat for energy. During light to moderate aerobic exercise, such as jogging, stored fat provides 50 to 60 percent of the fuel. When you exercise hard, as in sprinting, racing, lifting weights, or other intense exercise, you rely primarily on glycogen stores. Unfortunately, for competitive athletes, fat cannot be used exclusively as fuel because the muscles need a certain amount of carbohydrate to function well at high intensities, such as a surge up a hill or a sprint to the finish. Fitness exercisers can get away with a lower carbohydrate intake than elite athletes who push themselves to exhaustion can.
Biochemical changes that occur during training influence the amount of glycogen you can store in your muscles. The figures that follow indicate that well-trained muscles store 20 to 50 percent more glycogen than untrained muscles do (Costill et al. 1981; Sherman et al. 1981). This change enhances endurance capacity and is one reason a novice runner can't just load up on carbohydrate and run a top-quality marathon (table 6.3).
Because of the unfounded fears that carbohydrate is fattening or the belief that you need a high-protein diet to build muscle or a high-fat diet for endurance, many athletes today are skimping on carbohydrate foods. Some go on the paleo diet or keto diet; others go gluten free. The resulting low-carbohydrate intake can potentially hurt performance; it contrasts sharply with the diet of 2.5 to 4.5 grams of carbohydrate per pound of body weight (5 to 10 g/kg)—or 55 to 65 percent carbohydrate—recommended by most exercise and health professionals for people who train for one to three hours a day.
A case in point is ice hockey, an incredibly intense sport that relies on both muscular strength and power. During a game, carbohydrate is the primary fuel, and muscle carbohydrate (glycogen) stores decline between 38 and 88 percent. Muscle glycogen depletion relates closely to muscular fatigue. A motion analysis of elite ice hockey teams showed that the players with a high-carbohydrate (60 percent) diet skated not only 30 percent more distance but also faster than the players who ate their standard low-carbohydrate (40 percent) diet. In the final period of the game, which often determines whether a team wins or loses, the high-carbohydrate group skated 11 percent more distance than they did in the first period; the low-carbohydrate group skated 14 percent less. The researchers reached the following conclusions (Ackermark et al. 1996):
- Low muscle glycogen stores at the start of the game can jeopardize performance at the end of the game.
- Three days between games (with training on two of those days) plus a low-carbohydrate (40 percent) diet does not replace normal muscle glycogen stores (the players in the high-carbohydrate group had 45 percent more glycogen).
- The differences in performance between the well-fueled players and those who ate inadequate carbohydrate were most evident in the last period of the game.
Whether your sport is ice hockey, soccer, rugby, football, basketball, or any intense sport, remember to eat responsibly. Make carbohydrate the foundation of each meal and protein the accompaniment.
After exercise, it is important to consume carbohydrate to replenish muscle glycogen stores. In a landmark study, exercise physiologist J. Bergstrom and his colleagues (1967) compared the rate at which muscle glycogen was replaced in subjects who exercised to exhaustion and then ate either a high-protein, high-fat diet, or a high-carbohydrate diet. The subjects on the high-protein, high-fat diet (similar to an Atkins or other high-protein, low-carbohydrate diet with abundant eggs, chicken, beef, cheese, and nuts) remained glycogen depleted for five days (figure 6.1). The subjects on the high-carbohydrate diet totally replenished their muscle glycogen in two days. This result shows that protein and fat aren't stored as muscle glycogen and that carbohydrate is important for replacing depleted glycogen stores. Other research suggests that three sets of biceps curls (8 to 10 repetitions per set) reduce muscle glycogen by 35 percent (Martin, Armstrong, and Rodriquez 2005). With repeated days of low carbohydrate and high repetitions, the muscles of bodybuilders and marathon runners can soon become depleted. Hence, every athlete should eat meals in which two-thirds of the plate is dedicated to wholesome carbohydrates (grains, vegetables, fruits) and one-third to protein.
Carbohydrate: simplifying a complex topic
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet.
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet. I constantly study the research and remain convinced that wholesome forms of carbohydrate are the best choices for both athletes and fitness exercisers for fueling your muscles and promoting good health. In this chapter, I will explain why.
People of all ages and athletic abilities will benefit from nourishing themselves with minimally processed carbohydrate-rich fruits, vegetables, beans, legumes, and whole-grain foods, along with the right balance of protein and healthy fats. But why do some athletes insist they feel better when they stop eating bread, cereal, and pasta? Carolyn, an avid triathlete, raved about how much better she felt after having cut out carbs. I asked, “What were you eating before you made this change?” Her answer indicated the Standard American diet (SAD), with skipped meals, abundant fast foods, and more junk snacks than high-quality meals. No wonder she felt better when she started eating better.
Other reasons for feeling so much better after giving up “carbs” might relate to food sensitivities. When you cut out a lot of foods, you eliminate the one or two items that might create feelings of unwellness. A registered dietitian can help you reach the same level of feeling great by working with you to figure out which foods contribute to the sensitivity.
Some athletes embrace a carb-free diet as a way to curb sugar binges that lead to eating too many carbs. An easier way to reduce carb binges is to prevent extreme hunger. Despite popular belief, carb binges are unlikely caused by being addicted to carbs, but rather caused by the physiological effects of hunger. Refer to chapters 5 (sweet cravings) and 16 (weight management).
The purpose of this chapter is to eliminate this confusion so you can make choices that best promote good health, appropriate weight, and optimal sports performance.
Simple and Complex Carbohydrates
The carbohydrate family includes both simple and complex carbohydrates. The simple carbohydrates are monosaccharides and disaccharides (single- and double-sugar molecules). Glucose, fructose, and galactose are monosaccharides, the simplest sugars, and can be symbolized like this:
The disaccharides can be symbolized like this:
Four common sources of disaccharides are table sugar (sucrose), milk sugar (lactose, a combination of glucose and galactose), corn syrup, and honey.
Table sugar, corn syrup, and honey all contain glucose and fructose but in different amounts.
- Table sugar, upon digestion, breaks apart into 50 percent glucose and 50 percent fructose.
- High-fructose corn syrup (HFCS), commonly used in soft drinks, breaks down to about 55 percent fructose and 45 percent glucose. (HFCS is made using chemical processes that first convert cornstarch to corn syrup and then convert about 55 percent of the glucose in the corn syrup to fructose to make it taste sweeter.)
- Honey contains about 31 percent glucose, 38 percent fructose, 10 percent other sugars, 17 percent water, and 4 percent miscellaneous particles.
Your body eventually converts all monosaccharides and disaccharides to glucose, which travels in the blood (blood glucose) to fuel your muscles and brain.
Fruits and vegetables offer a variety of sugars in differing proportions. Because you absorb different sugars at different rates and by differing pathways, research indicates that consuming a variety of sugars allows for better absorption during exercise. This means that you should read the ingredient label on your sports drink to be sure it offers more than one type of sugar.
Honey has been mistakenly described as being superior to HFCS or refined white sugar. If you prefer honey because of the pleasant taste, fine. But it's not superior in terms of vitamins or performance. Sugar in any form—honey, maple syrup, corn syrup, brown sugar, raw sugar, or agave—offers insignificant nutritional value, and your body digests any type of sugar or carbohydrate into glucose before using it for fuel.
Another type of sugar that is found in many engineered sports foods is maltodextrins, also called glucose polymers. Maltodextrins are chains of about five glucose molecules. Sports drinks sweetened with maltodextrins can provide energy with rapid absorption and less sweetness than regular sugar provides. Sports fuels that use maltodextrins include Hammer Nutrition products.
Complex carbohydrates, such as starch in plant foods and glycogen in muscles, are formed when sugars link together to form long complex chains, similar to a string of hundreds of pearls. They can be symbolized like this:
Plants store extra sugar in the form of starch. For example, corn is sweet when it's young, but it becomes starchy as it gets older. Its extra sugar converts into starch. In contrast to corn and other vegetables, fruits tend to convert starch into sugar as they ripen. A good example is the banana:
- A green banana with some yellow is 80 percent starch and 7 percent sugar.
- A mostly yellow banana is 25 percent starch and 65 percent sugar.
- A spotted and speckled banana is 5 percent starch and 90 percent sugar.
The potatoes, rice, bread, and other starches you eat are digested into glucose and then burned for energy or stored for future use. Humans store extra glucose mostly in the form of muscle glycogen and liver glycogen (but generally not as body fat). This glycogen is readily available for energy during exercise.
Sugars and starches have similar abilities to fuel muscles but different abilities to nourish them with vitamins and minerals:
- The refined carbohydrate in sugary soft drinks provides energy but no vitamins or minerals.
- The highly processed carbohydrate in sports drinks, candies, and gels provides energy but no vitamins or minerals, unless the foods are fortified.
- The natural sugars and unrefined carbohydrate in fruits, vegetables, and whole grains provide energy, vitamins, minerals, fiber, and phytochemicals—the fuel and spark plugs that your body's engine needs to function best.
Protein and the vegetarian
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods.
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods. They may find animal protein hard to digest or believe it is bad for their health, unethical to eat, or erosive to the environment. (Cattle are a source of greenhouse gas that contributes to global warming.) Meatless Mondays (and other days, too) are a good idea for the planet! And a balanced vegetarian diet is indeed a good investment in good health. A plant-based diet tends to have more fiber, less saturated fat, and more phytochemicals—active compounds that bolster the immune system, reduce inflammation, and are health protective.
The trick to eating a balanced vegetarian diet is to make the effort to replace meat with plant proteins. That is, if you eliminate the meatballs from your pasta dinner, add an alternative source of plant-based protein. Do not simply fuel up only on pasta and neglect your protein needs. You can get adequate protein to support your sports program by including kidney beans, chickpeas, hummus, nut butter, tofu, nuts, veggie burgers, edamame, and other forms of plant protein in each meal.
Tofu (soybean curd) and other soy products, such as soy burgers and soy milk, are smart additions to a meat-free diet. They contain a source of high-quality protein that is similar in value to animal protein. Note that a Boca Burger (soy protein) has far less protein than a hamburger, however (refer to table 7.2). Despite popular belief among male athletes, the plant estrogens in soy do not have a feminizing effect, do not reduce testosterone levels, and do not impair fertility (Messina 2010). All athletes can enjoy soy foods in moderation, as with any food, as a health-promoting part of a balanced sports diet.
For lacto-vegetarians (who consume dairy foods), milk and (Greek) yogurt are simple ways to add extra high-quality protein to meals and snacks. Although they have been given a bad rap because they are high in saturated fat, recent studies question whether a connection exits between dairy fat and heart disease and stroke regardless of the milk fat levels (de Oliveira Otto et al. 2018). This controversial topic is worthy of continued research, so until the American Heart Association gives the green light for full-fat dairy foods, a wise plan is to choose mostly reduced-fat dairy foods and balance full-fat choices into an overall healthy eating pattern. That said, blue cheese and other “moldy cheeses” may be a positive addition to the diet regardless of their saturated fat: They support gut bacteria that promote good health (Petyaev and Bashmakov 2012).
Milk, other dairy foods, eggs, and all animal sources of protein contain all the essential amino acids and are often referred to as complete proteins. The protein in soy foods such as tofu, tempeh, edamame, and soy milk are also complete proteins. The protein in rice, beans, pasta, lentils, nuts, fruits, vegetables, and other plant foods are incomplete because they contain low levels of some of the essential amino acids. Therefore, vegetarians must eat a variety of foods to get a variety of amino acids that combine with incomplete proteins to make them complete. Vegetarians who drink milk can easily do this by adding soy milk or dairy products to each meal, for example, combining (soy) milk with oatmeal or sprinkling grated low-fat (soy) cheese on beans. Note that rice and almond milks are not nutritionally equal to soy milk, but rather are very poor protein sources (see chapter 1).
Vegans (strict vegetarians who eat no dairy, eggs, or animal protein) need to consistently eat a variety of foods to optimize their intake of a variety of amino acids over the course of the day. The following combinations work particularly well together; they complement each other by boosting the limiting amino acid:
- Grains plus beans or legumes, such as rice and beans, bread and split-pea soup, tofu and brown rice, corn bread and chili with kidney beans
- Legumes plus seeds, such as chickpeas and tahini (as in hummus), tofu and sesame seeds
- Added soy products (or dairy, if nonvegan), such as cereal and (soy) milk, baked potato and Greek or soy yogurt, hummus wrap with low-fat (soy) cheese
By following these guidelines, vegetarian athletes can consume an adequate amount of complete protein every day. They may, however, lack iron and zinc, minerals found primarily in meats and other animal products. Vegans also need to be sure they get adequate riboflavin, calcium, and vitamin B12, either through a supplement or from carefully selected food sources.
Why carbohydrates are important for active people
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again.
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again. They are not fattening, and you need them to fuel your muscles so that you can enjoy your exercise program.
The average 150-pound (68 kg) man has about 1,800 calories of carbohydrate stored in the liver, muscles, blood, and body fluids in approximately the distribution shown in table 6.2.
The carbohydrate in the muscles is used during exercise. The carbohydrate in the liver is released into the bloodstream to maintain a normal blood glucose level and feed the brain (as well as the muscles). These limited carbohydrate stores influence how long you can enjoy exercising. When your glycogen stores get too low, you hit the wall—that is, you feel overwhelmingly fatigued and yearn to quit. In a research study, cyclists with depleted muscle glycogen stores were able to exercise only 55 minutes to fatigue (as measured by an inability to maintain a specified pedaling speed on a stationary bicycle), as compared with more than twice as long—about 120 minutes—when they were carbohydrate loaded (Green et al. 2007). Food works!
In comparison to the approximately 1,800 calories of stored carbohydrate, the average lean 150-pound (68 kg) man also has 60,000 to 100,000 calories of stored fat—enough to run hundreds of miles. During low-level exercise such as walking, the muscles burn primarily fat for energy. During light to moderate aerobic exercise, such as jogging, stored fat provides 50 to 60 percent of the fuel. When you exercise hard, as in sprinting, racing, lifting weights, or other intense exercise, you rely primarily on glycogen stores. Unfortunately, for competitive athletes, fat cannot be used exclusively as fuel because the muscles need a certain amount of carbohydrate to function well at high intensities, such as a surge up a hill or a sprint to the finish. Fitness exercisers can get away with a lower carbohydrate intake than elite athletes who push themselves to exhaustion can.
Biochemical changes that occur during training influence the amount of glycogen you can store in your muscles. The figures that follow indicate that well-trained muscles store 20 to 50 percent more glycogen than untrained muscles do (Costill et al. 1981; Sherman et al. 1981). This change enhances endurance capacity and is one reason a novice runner can't just load up on carbohydrate and run a top-quality marathon (table 6.3).
Because of the unfounded fears that carbohydrate is fattening or the belief that you need a high-protein diet to build muscle or a high-fat diet for endurance, many athletes today are skimping on carbohydrate foods. Some go on the paleo diet or keto diet; others go gluten free. The resulting low-carbohydrate intake can potentially hurt performance; it contrasts sharply with the diet of 2.5 to 4.5 grams of carbohydrate per pound of body weight (5 to 10 g/kg)—or 55 to 65 percent carbohydrate—recommended by most exercise and health professionals for people who train for one to three hours a day.
A case in point is ice hockey, an incredibly intense sport that relies on both muscular strength and power. During a game, carbohydrate is the primary fuel, and muscle carbohydrate (glycogen) stores decline between 38 and 88 percent. Muscle glycogen depletion relates closely to muscular fatigue. A motion analysis of elite ice hockey teams showed that the players with a high-carbohydrate (60 percent) diet skated not only 30 percent more distance but also faster than the players who ate their standard low-carbohydrate (40 percent) diet. In the final period of the game, which often determines whether a team wins or loses, the high-carbohydrate group skated 11 percent more distance than they did in the first period; the low-carbohydrate group skated 14 percent less. The researchers reached the following conclusions (Ackermark et al. 1996):
- Low muscle glycogen stores at the start of the game can jeopardize performance at the end of the game.
- Three days between games (with training on two of those days) plus a low-carbohydrate (40 percent) diet does not replace normal muscle glycogen stores (the players in the high-carbohydrate group had 45 percent more glycogen).
- The differences in performance between the well-fueled players and those who ate inadequate carbohydrate were most evident in the last period of the game.
Whether your sport is ice hockey, soccer, rugby, football, basketball, or any intense sport, remember to eat responsibly. Make carbohydrate the foundation of each meal and protein the accompaniment.
After exercise, it is important to consume carbohydrate to replenish muscle glycogen stores. In a landmark study, exercise physiologist J. Bergstrom and his colleagues (1967) compared the rate at which muscle glycogen was replaced in subjects who exercised to exhaustion and then ate either a high-protein, high-fat diet, or a high-carbohydrate diet. The subjects on the high-protein, high-fat diet (similar to an Atkins or other high-protein, low-carbohydrate diet with abundant eggs, chicken, beef, cheese, and nuts) remained glycogen depleted for five days (figure 6.1). The subjects on the high-carbohydrate diet totally replenished their muscle glycogen in two days. This result shows that protein and fat aren't stored as muscle glycogen and that carbohydrate is important for replacing depleted glycogen stores. Other research suggests that three sets of biceps curls (8 to 10 repetitions per set) reduce muscle glycogen by 35 percent (Martin, Armstrong, and Rodriquez 2005). With repeated days of low carbohydrate and high repetitions, the muscles of bodybuilders and marathon runners can soon become depleted. Hence, every athlete should eat meals in which two-thirds of the plate is dedicated to wholesome carbohydrates (grains, vegetables, fruits) and one-third to protein.
Carbohydrate: simplifying a complex topic
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet.
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet. I constantly study the research and remain convinced that wholesome forms of carbohydrate are the best choices for both athletes and fitness exercisers for fueling your muscles and promoting good health. In this chapter, I will explain why.
People of all ages and athletic abilities will benefit from nourishing themselves with minimally processed carbohydrate-rich fruits, vegetables, beans, legumes, and whole-grain foods, along with the right balance of protein and healthy fats. But why do some athletes insist they feel better when they stop eating bread, cereal, and pasta? Carolyn, an avid triathlete, raved about how much better she felt after having cut out carbs. I asked, “What were you eating before you made this change?” Her answer indicated the Standard American diet (SAD), with skipped meals, abundant fast foods, and more junk snacks than high-quality meals. No wonder she felt better when she started eating better.
Other reasons for feeling so much better after giving up “carbs” might relate to food sensitivities. When you cut out a lot of foods, you eliminate the one or two items that might create feelings of unwellness. A registered dietitian can help you reach the same level of feeling great by working with you to figure out which foods contribute to the sensitivity.
Some athletes embrace a carb-free diet as a way to curb sugar binges that lead to eating too many carbs. An easier way to reduce carb binges is to prevent extreme hunger. Despite popular belief, carb binges are unlikely caused by being addicted to carbs, but rather caused by the physiological effects of hunger. Refer to chapters 5 (sweet cravings) and 16 (weight management).
The purpose of this chapter is to eliminate this confusion so you can make choices that best promote good health, appropriate weight, and optimal sports performance.
Simple and Complex Carbohydrates
The carbohydrate family includes both simple and complex carbohydrates. The simple carbohydrates are monosaccharides and disaccharides (single- and double-sugar molecules). Glucose, fructose, and galactose are monosaccharides, the simplest sugars, and can be symbolized like this:
The disaccharides can be symbolized like this:
Four common sources of disaccharides are table sugar (sucrose), milk sugar (lactose, a combination of glucose and galactose), corn syrup, and honey.
Table sugar, corn syrup, and honey all contain glucose and fructose but in different amounts.
- Table sugar, upon digestion, breaks apart into 50 percent glucose and 50 percent fructose.
- High-fructose corn syrup (HFCS), commonly used in soft drinks, breaks down to about 55 percent fructose and 45 percent glucose. (HFCS is made using chemical processes that first convert cornstarch to corn syrup and then convert about 55 percent of the glucose in the corn syrup to fructose to make it taste sweeter.)
- Honey contains about 31 percent glucose, 38 percent fructose, 10 percent other sugars, 17 percent water, and 4 percent miscellaneous particles.
Your body eventually converts all monosaccharides and disaccharides to glucose, which travels in the blood (blood glucose) to fuel your muscles and brain.
Fruits and vegetables offer a variety of sugars in differing proportions. Because you absorb different sugars at different rates and by differing pathways, research indicates that consuming a variety of sugars allows for better absorption during exercise. This means that you should read the ingredient label on your sports drink to be sure it offers more than one type of sugar.
Honey has been mistakenly described as being superior to HFCS or refined white sugar. If you prefer honey because of the pleasant taste, fine. But it's not superior in terms of vitamins or performance. Sugar in any form—honey, maple syrup, corn syrup, brown sugar, raw sugar, or agave—offers insignificant nutritional value, and your body digests any type of sugar or carbohydrate into glucose before using it for fuel.
Another type of sugar that is found in many engineered sports foods is maltodextrins, also called glucose polymers. Maltodextrins are chains of about five glucose molecules. Sports drinks sweetened with maltodextrins can provide energy with rapid absorption and less sweetness than regular sugar provides. Sports fuels that use maltodextrins include Hammer Nutrition products.
Complex carbohydrates, such as starch in plant foods and glycogen in muscles, are formed when sugars link together to form long complex chains, similar to a string of hundreds of pearls. They can be symbolized like this:
Plants store extra sugar in the form of starch. For example, corn is sweet when it's young, but it becomes starchy as it gets older. Its extra sugar converts into starch. In contrast to corn and other vegetables, fruits tend to convert starch into sugar as they ripen. A good example is the banana:
- A green banana with some yellow is 80 percent starch and 7 percent sugar.
- A mostly yellow banana is 25 percent starch and 65 percent sugar.
- A spotted and speckled banana is 5 percent starch and 90 percent sugar.
The potatoes, rice, bread, and other starches you eat are digested into glucose and then burned for energy or stored for future use. Humans store extra glucose mostly in the form of muscle glycogen and liver glycogen (but generally not as body fat). This glycogen is readily available for energy during exercise.
Sugars and starches have similar abilities to fuel muscles but different abilities to nourish them with vitamins and minerals:
- The refined carbohydrate in sugary soft drinks provides energy but no vitamins or minerals.
- The highly processed carbohydrate in sports drinks, candies, and gels provides energy but no vitamins or minerals, unless the foods are fortified.
- The natural sugars and unrefined carbohydrate in fruits, vegetables, and whole grains provide energy, vitamins, minerals, fiber, and phytochemicals—the fuel and spark plugs that your body's engine needs to function best.
Protein and the vegetarian
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods.
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods. They may find animal protein hard to digest or believe it is bad for their health, unethical to eat, or erosive to the environment. (Cattle are a source of greenhouse gas that contributes to global warming.) Meatless Mondays (and other days, too) are a good idea for the planet! And a balanced vegetarian diet is indeed a good investment in good health. A plant-based diet tends to have more fiber, less saturated fat, and more phytochemicals—active compounds that bolster the immune system, reduce inflammation, and are health protective.
The trick to eating a balanced vegetarian diet is to make the effort to replace meat with plant proteins. That is, if you eliminate the meatballs from your pasta dinner, add an alternative source of plant-based protein. Do not simply fuel up only on pasta and neglect your protein needs. You can get adequate protein to support your sports program by including kidney beans, chickpeas, hummus, nut butter, tofu, nuts, veggie burgers, edamame, and other forms of plant protein in each meal.
Tofu (soybean curd) and other soy products, such as soy burgers and soy milk, are smart additions to a meat-free diet. They contain a source of high-quality protein that is similar in value to animal protein. Note that a Boca Burger (soy protein) has far less protein than a hamburger, however (refer to table 7.2). Despite popular belief among male athletes, the plant estrogens in soy do not have a feminizing effect, do not reduce testosterone levels, and do not impair fertility (Messina 2010). All athletes can enjoy soy foods in moderation, as with any food, as a health-promoting part of a balanced sports diet.
For lacto-vegetarians (who consume dairy foods), milk and (Greek) yogurt are simple ways to add extra high-quality protein to meals and snacks. Although they have been given a bad rap because they are high in saturated fat, recent studies question whether a connection exits between dairy fat and heart disease and stroke regardless of the milk fat levels (de Oliveira Otto et al. 2018). This controversial topic is worthy of continued research, so until the American Heart Association gives the green light for full-fat dairy foods, a wise plan is to choose mostly reduced-fat dairy foods and balance full-fat choices into an overall healthy eating pattern. That said, blue cheese and other “moldy cheeses” may be a positive addition to the diet regardless of their saturated fat: They support gut bacteria that promote good health (Petyaev and Bashmakov 2012).
Milk, other dairy foods, eggs, and all animal sources of protein contain all the essential amino acids and are often referred to as complete proteins. The protein in soy foods such as tofu, tempeh, edamame, and soy milk are also complete proteins. The protein in rice, beans, pasta, lentils, nuts, fruits, vegetables, and other plant foods are incomplete because they contain low levels of some of the essential amino acids. Therefore, vegetarians must eat a variety of foods to get a variety of amino acids that combine with incomplete proteins to make them complete. Vegetarians who drink milk can easily do this by adding soy milk or dairy products to each meal, for example, combining (soy) milk with oatmeal or sprinkling grated low-fat (soy) cheese on beans. Note that rice and almond milks are not nutritionally equal to soy milk, but rather are very poor protein sources (see chapter 1).
Vegans (strict vegetarians who eat no dairy, eggs, or animal protein) need to consistently eat a variety of foods to optimize their intake of a variety of amino acids over the course of the day. The following combinations work particularly well together; they complement each other by boosting the limiting amino acid:
- Grains plus beans or legumes, such as rice and beans, bread and split-pea soup, tofu and brown rice, corn bread and chili with kidney beans
- Legumes plus seeds, such as chickpeas and tahini (as in hummus), tofu and sesame seeds
- Added soy products (or dairy, if nonvegan), such as cereal and (soy) milk, baked potato and Greek or soy yogurt, hummus wrap with low-fat (soy) cheese
By following these guidelines, vegetarian athletes can consume an adequate amount of complete protein every day. They may, however, lack iron and zinc, minerals found primarily in meats and other animal products. Vegans also need to be sure they get adequate riboflavin, calcium, and vitamin B12, either through a supplement or from carefully selected food sources.
Why carbohydrates are important for active people
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again.
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again. They are not fattening, and you need them to fuel your muscles so that you can enjoy your exercise program.
The average 150-pound (68 kg) man has about 1,800 calories of carbohydrate stored in the liver, muscles, blood, and body fluids in approximately the distribution shown in table 6.2.
The carbohydrate in the muscles is used during exercise. The carbohydrate in the liver is released into the bloodstream to maintain a normal blood glucose level and feed the brain (as well as the muscles). These limited carbohydrate stores influence how long you can enjoy exercising. When your glycogen stores get too low, you hit the wall—that is, you feel overwhelmingly fatigued and yearn to quit. In a research study, cyclists with depleted muscle glycogen stores were able to exercise only 55 minutes to fatigue (as measured by an inability to maintain a specified pedaling speed on a stationary bicycle), as compared with more than twice as long—about 120 minutes—when they were carbohydrate loaded (Green et al. 2007). Food works!
In comparison to the approximately 1,800 calories of stored carbohydrate, the average lean 150-pound (68 kg) man also has 60,000 to 100,000 calories of stored fat—enough to run hundreds of miles. During low-level exercise such as walking, the muscles burn primarily fat for energy. During light to moderate aerobic exercise, such as jogging, stored fat provides 50 to 60 percent of the fuel. When you exercise hard, as in sprinting, racing, lifting weights, or other intense exercise, you rely primarily on glycogen stores. Unfortunately, for competitive athletes, fat cannot be used exclusively as fuel because the muscles need a certain amount of carbohydrate to function well at high intensities, such as a surge up a hill or a sprint to the finish. Fitness exercisers can get away with a lower carbohydrate intake than elite athletes who push themselves to exhaustion can.
Biochemical changes that occur during training influence the amount of glycogen you can store in your muscles. The figures that follow indicate that well-trained muscles store 20 to 50 percent more glycogen than untrained muscles do (Costill et al. 1981; Sherman et al. 1981). This change enhances endurance capacity and is one reason a novice runner can't just load up on carbohydrate and run a top-quality marathon (table 6.3).
Because of the unfounded fears that carbohydrate is fattening or the belief that you need a high-protein diet to build muscle or a high-fat diet for endurance, many athletes today are skimping on carbohydrate foods. Some go on the paleo diet or keto diet; others go gluten free. The resulting low-carbohydrate intake can potentially hurt performance; it contrasts sharply with the diet of 2.5 to 4.5 grams of carbohydrate per pound of body weight (5 to 10 g/kg)—or 55 to 65 percent carbohydrate—recommended by most exercise and health professionals for people who train for one to three hours a day.
A case in point is ice hockey, an incredibly intense sport that relies on both muscular strength and power. During a game, carbohydrate is the primary fuel, and muscle carbohydrate (glycogen) stores decline between 38 and 88 percent. Muscle glycogen depletion relates closely to muscular fatigue. A motion analysis of elite ice hockey teams showed that the players with a high-carbohydrate (60 percent) diet skated not only 30 percent more distance but also faster than the players who ate their standard low-carbohydrate (40 percent) diet. In the final period of the game, which often determines whether a team wins or loses, the high-carbohydrate group skated 11 percent more distance than they did in the first period; the low-carbohydrate group skated 14 percent less. The researchers reached the following conclusions (Ackermark et al. 1996):
- Low muscle glycogen stores at the start of the game can jeopardize performance at the end of the game.
- Three days between games (with training on two of those days) plus a low-carbohydrate (40 percent) diet does not replace normal muscle glycogen stores (the players in the high-carbohydrate group had 45 percent more glycogen).
- The differences in performance between the well-fueled players and those who ate inadequate carbohydrate were most evident in the last period of the game.
Whether your sport is ice hockey, soccer, rugby, football, basketball, or any intense sport, remember to eat responsibly. Make carbohydrate the foundation of each meal and protein the accompaniment.
After exercise, it is important to consume carbohydrate to replenish muscle glycogen stores. In a landmark study, exercise physiologist J. Bergstrom and his colleagues (1967) compared the rate at which muscle glycogen was replaced in subjects who exercised to exhaustion and then ate either a high-protein, high-fat diet, or a high-carbohydrate diet. The subjects on the high-protein, high-fat diet (similar to an Atkins or other high-protein, low-carbohydrate diet with abundant eggs, chicken, beef, cheese, and nuts) remained glycogen depleted for five days (figure 6.1). The subjects on the high-carbohydrate diet totally replenished their muscle glycogen in two days. This result shows that protein and fat aren't stored as muscle glycogen and that carbohydrate is important for replacing depleted glycogen stores. Other research suggests that three sets of biceps curls (8 to 10 repetitions per set) reduce muscle glycogen by 35 percent (Martin, Armstrong, and Rodriquez 2005). With repeated days of low carbohydrate and high repetitions, the muscles of bodybuilders and marathon runners can soon become depleted. Hence, every athlete should eat meals in which two-thirds of the plate is dedicated to wholesome carbohydrates (grains, vegetables, fruits) and one-third to protein.
Carbohydrate: simplifying a complex topic
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet.
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet. I constantly study the research and remain convinced that wholesome forms of carbohydrate are the best choices for both athletes and fitness exercisers for fueling your muscles and promoting good health. In this chapter, I will explain why.
People of all ages and athletic abilities will benefit from nourishing themselves with minimally processed carbohydrate-rich fruits, vegetables, beans, legumes, and whole-grain foods, along with the right balance of protein and healthy fats. But why do some athletes insist they feel better when they stop eating bread, cereal, and pasta? Carolyn, an avid triathlete, raved about how much better she felt after having cut out carbs. I asked, “What were you eating before you made this change?” Her answer indicated the Standard American diet (SAD), with skipped meals, abundant fast foods, and more junk snacks than high-quality meals. No wonder she felt better when she started eating better.
Other reasons for feeling so much better after giving up “carbs” might relate to food sensitivities. When you cut out a lot of foods, you eliminate the one or two items that might create feelings of unwellness. A registered dietitian can help you reach the same level of feeling great by working with you to figure out which foods contribute to the sensitivity.
Some athletes embrace a carb-free diet as a way to curb sugar binges that lead to eating too many carbs. An easier way to reduce carb binges is to prevent extreme hunger. Despite popular belief, carb binges are unlikely caused by being addicted to carbs, but rather caused by the physiological effects of hunger. Refer to chapters 5 (sweet cravings) and 16 (weight management).
The purpose of this chapter is to eliminate this confusion so you can make choices that best promote good health, appropriate weight, and optimal sports performance.
Simple and Complex Carbohydrates
The carbohydrate family includes both simple and complex carbohydrates. The simple carbohydrates are monosaccharides and disaccharides (single- and double-sugar molecules). Glucose, fructose, and galactose are monosaccharides, the simplest sugars, and can be symbolized like this:
The disaccharides can be symbolized like this:
Four common sources of disaccharides are table sugar (sucrose), milk sugar (lactose, a combination of glucose and galactose), corn syrup, and honey.
Table sugar, corn syrup, and honey all contain glucose and fructose but in different amounts.
- Table sugar, upon digestion, breaks apart into 50 percent glucose and 50 percent fructose.
- High-fructose corn syrup (HFCS), commonly used in soft drinks, breaks down to about 55 percent fructose and 45 percent glucose. (HFCS is made using chemical processes that first convert cornstarch to corn syrup and then convert about 55 percent of the glucose in the corn syrup to fructose to make it taste sweeter.)
- Honey contains about 31 percent glucose, 38 percent fructose, 10 percent other sugars, 17 percent water, and 4 percent miscellaneous particles.
Your body eventually converts all monosaccharides and disaccharides to glucose, which travels in the blood (blood glucose) to fuel your muscles and brain.
Fruits and vegetables offer a variety of sugars in differing proportions. Because you absorb different sugars at different rates and by differing pathways, research indicates that consuming a variety of sugars allows for better absorption during exercise. This means that you should read the ingredient label on your sports drink to be sure it offers more than one type of sugar.
Honey has been mistakenly described as being superior to HFCS or refined white sugar. If you prefer honey because of the pleasant taste, fine. But it's not superior in terms of vitamins or performance. Sugar in any form—honey, maple syrup, corn syrup, brown sugar, raw sugar, or agave—offers insignificant nutritional value, and your body digests any type of sugar or carbohydrate into glucose before using it for fuel.
Another type of sugar that is found in many engineered sports foods is maltodextrins, also called glucose polymers. Maltodextrins are chains of about five glucose molecules. Sports drinks sweetened with maltodextrins can provide energy with rapid absorption and less sweetness than regular sugar provides. Sports fuels that use maltodextrins include Hammer Nutrition products.
Complex carbohydrates, such as starch in plant foods and glycogen in muscles, are formed when sugars link together to form long complex chains, similar to a string of hundreds of pearls. They can be symbolized like this:
Plants store extra sugar in the form of starch. For example, corn is sweet when it's young, but it becomes starchy as it gets older. Its extra sugar converts into starch. In contrast to corn and other vegetables, fruits tend to convert starch into sugar as they ripen. A good example is the banana:
- A green banana with some yellow is 80 percent starch and 7 percent sugar.
- A mostly yellow banana is 25 percent starch and 65 percent sugar.
- A spotted and speckled banana is 5 percent starch and 90 percent sugar.
The potatoes, rice, bread, and other starches you eat are digested into glucose and then burned for energy or stored for future use. Humans store extra glucose mostly in the form of muscle glycogen and liver glycogen (but generally not as body fat). This glycogen is readily available for energy during exercise.
Sugars and starches have similar abilities to fuel muscles but different abilities to nourish them with vitamins and minerals:
- The refined carbohydrate in sugary soft drinks provides energy but no vitamins or minerals.
- The highly processed carbohydrate in sports drinks, candies, and gels provides energy but no vitamins or minerals, unless the foods are fortified.
- The natural sugars and unrefined carbohydrate in fruits, vegetables, and whole grains provide energy, vitamins, minerals, fiber, and phytochemicals—the fuel and spark plugs that your body's engine needs to function best.
Protein and the vegetarian
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods.
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods. They may find animal protein hard to digest or believe it is bad for their health, unethical to eat, or erosive to the environment. (Cattle are a source of greenhouse gas that contributes to global warming.) Meatless Mondays (and other days, too) are a good idea for the planet! And a balanced vegetarian diet is indeed a good investment in good health. A plant-based diet tends to have more fiber, less saturated fat, and more phytochemicals—active compounds that bolster the immune system, reduce inflammation, and are health protective.
The trick to eating a balanced vegetarian diet is to make the effort to replace meat with plant proteins. That is, if you eliminate the meatballs from your pasta dinner, add an alternative source of plant-based protein. Do not simply fuel up only on pasta and neglect your protein needs. You can get adequate protein to support your sports program by including kidney beans, chickpeas, hummus, nut butter, tofu, nuts, veggie burgers, edamame, and other forms of plant protein in each meal.
Tofu (soybean curd) and other soy products, such as soy burgers and soy milk, are smart additions to a meat-free diet. They contain a source of high-quality protein that is similar in value to animal protein. Note that a Boca Burger (soy protein) has far less protein than a hamburger, however (refer to table 7.2). Despite popular belief among male athletes, the plant estrogens in soy do not have a feminizing effect, do not reduce testosterone levels, and do not impair fertility (Messina 2010). All athletes can enjoy soy foods in moderation, as with any food, as a health-promoting part of a balanced sports diet.
For lacto-vegetarians (who consume dairy foods), milk and (Greek) yogurt are simple ways to add extra high-quality protein to meals and snacks. Although they have been given a bad rap because they are high in saturated fat, recent studies question whether a connection exits between dairy fat and heart disease and stroke regardless of the milk fat levels (de Oliveira Otto et al. 2018). This controversial topic is worthy of continued research, so until the American Heart Association gives the green light for full-fat dairy foods, a wise plan is to choose mostly reduced-fat dairy foods and balance full-fat choices into an overall healthy eating pattern. That said, blue cheese and other “moldy cheeses” may be a positive addition to the diet regardless of their saturated fat: They support gut bacteria that promote good health (Petyaev and Bashmakov 2012).
Milk, other dairy foods, eggs, and all animal sources of protein contain all the essential amino acids and are often referred to as complete proteins. The protein in soy foods such as tofu, tempeh, edamame, and soy milk are also complete proteins. The protein in rice, beans, pasta, lentils, nuts, fruits, vegetables, and other plant foods are incomplete because they contain low levels of some of the essential amino acids. Therefore, vegetarians must eat a variety of foods to get a variety of amino acids that combine with incomplete proteins to make them complete. Vegetarians who drink milk can easily do this by adding soy milk or dairy products to each meal, for example, combining (soy) milk with oatmeal or sprinkling grated low-fat (soy) cheese on beans. Note that rice and almond milks are not nutritionally equal to soy milk, but rather are very poor protein sources (see chapter 1).
Vegans (strict vegetarians who eat no dairy, eggs, or animal protein) need to consistently eat a variety of foods to optimize their intake of a variety of amino acids over the course of the day. The following combinations work particularly well together; they complement each other by boosting the limiting amino acid:
- Grains plus beans or legumes, such as rice and beans, bread and split-pea soup, tofu and brown rice, corn bread and chili with kidney beans
- Legumes plus seeds, such as chickpeas and tahini (as in hummus), tofu and sesame seeds
- Added soy products (or dairy, if nonvegan), such as cereal and (soy) milk, baked potato and Greek or soy yogurt, hummus wrap with low-fat (soy) cheese
By following these guidelines, vegetarian athletes can consume an adequate amount of complete protein every day. They may, however, lack iron and zinc, minerals found primarily in meats and other animal products. Vegans also need to be sure they get adequate riboflavin, calcium, and vitamin B12, either through a supplement or from carefully selected food sources.
Why carbohydrates are important for active people
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again.
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again. They are not fattening, and you need them to fuel your muscles so that you can enjoy your exercise program.
The average 150-pound (68 kg) man has about 1,800 calories of carbohydrate stored in the liver, muscles, blood, and body fluids in approximately the distribution shown in table 6.2.
The carbohydrate in the muscles is used during exercise. The carbohydrate in the liver is released into the bloodstream to maintain a normal blood glucose level and feed the brain (as well as the muscles). These limited carbohydrate stores influence how long you can enjoy exercising. When your glycogen stores get too low, you hit the wall—that is, you feel overwhelmingly fatigued and yearn to quit. In a research study, cyclists with depleted muscle glycogen stores were able to exercise only 55 minutes to fatigue (as measured by an inability to maintain a specified pedaling speed on a stationary bicycle), as compared with more than twice as long—about 120 minutes—when they were carbohydrate loaded (Green et al. 2007). Food works!
In comparison to the approximately 1,800 calories of stored carbohydrate, the average lean 150-pound (68 kg) man also has 60,000 to 100,000 calories of stored fat—enough to run hundreds of miles. During low-level exercise such as walking, the muscles burn primarily fat for energy. During light to moderate aerobic exercise, such as jogging, stored fat provides 50 to 60 percent of the fuel. When you exercise hard, as in sprinting, racing, lifting weights, or other intense exercise, you rely primarily on glycogen stores. Unfortunately, for competitive athletes, fat cannot be used exclusively as fuel because the muscles need a certain amount of carbohydrate to function well at high intensities, such as a surge up a hill or a sprint to the finish. Fitness exercisers can get away with a lower carbohydrate intake than elite athletes who push themselves to exhaustion can.
Biochemical changes that occur during training influence the amount of glycogen you can store in your muscles. The figures that follow indicate that well-trained muscles store 20 to 50 percent more glycogen than untrained muscles do (Costill et al. 1981; Sherman et al. 1981). This change enhances endurance capacity and is one reason a novice runner can't just load up on carbohydrate and run a top-quality marathon (table 6.3).
Because of the unfounded fears that carbohydrate is fattening or the belief that you need a high-protein diet to build muscle or a high-fat diet for endurance, many athletes today are skimping on carbohydrate foods. Some go on the paleo diet or keto diet; others go gluten free. The resulting low-carbohydrate intake can potentially hurt performance; it contrasts sharply with the diet of 2.5 to 4.5 grams of carbohydrate per pound of body weight (5 to 10 g/kg)—or 55 to 65 percent carbohydrate—recommended by most exercise and health professionals for people who train for one to three hours a day.
A case in point is ice hockey, an incredibly intense sport that relies on both muscular strength and power. During a game, carbohydrate is the primary fuel, and muscle carbohydrate (glycogen) stores decline between 38 and 88 percent. Muscle glycogen depletion relates closely to muscular fatigue. A motion analysis of elite ice hockey teams showed that the players with a high-carbohydrate (60 percent) diet skated not only 30 percent more distance but also faster than the players who ate their standard low-carbohydrate (40 percent) diet. In the final period of the game, which often determines whether a team wins or loses, the high-carbohydrate group skated 11 percent more distance than they did in the first period; the low-carbohydrate group skated 14 percent less. The researchers reached the following conclusions (Ackermark et al. 1996):
- Low muscle glycogen stores at the start of the game can jeopardize performance at the end of the game.
- Three days between games (with training on two of those days) plus a low-carbohydrate (40 percent) diet does not replace normal muscle glycogen stores (the players in the high-carbohydrate group had 45 percent more glycogen).
- The differences in performance between the well-fueled players and those who ate inadequate carbohydrate were most evident in the last period of the game.
Whether your sport is ice hockey, soccer, rugby, football, basketball, or any intense sport, remember to eat responsibly. Make carbohydrate the foundation of each meal and protein the accompaniment.
After exercise, it is important to consume carbohydrate to replenish muscle glycogen stores. In a landmark study, exercise physiologist J. Bergstrom and his colleagues (1967) compared the rate at which muscle glycogen was replaced in subjects who exercised to exhaustion and then ate either a high-protein, high-fat diet, or a high-carbohydrate diet. The subjects on the high-protein, high-fat diet (similar to an Atkins or other high-protein, low-carbohydrate diet with abundant eggs, chicken, beef, cheese, and nuts) remained glycogen depleted for five days (figure 6.1). The subjects on the high-carbohydrate diet totally replenished their muscle glycogen in two days. This result shows that protein and fat aren't stored as muscle glycogen and that carbohydrate is important for replacing depleted glycogen stores. Other research suggests that three sets of biceps curls (8 to 10 repetitions per set) reduce muscle glycogen by 35 percent (Martin, Armstrong, and Rodriquez 2005). With repeated days of low carbohydrate and high repetitions, the muscles of bodybuilders and marathon runners can soon become depleted. Hence, every athlete should eat meals in which two-thirds of the plate is dedicated to wholesome carbohydrates (grains, vegetables, fruits) and one-third to protein.
Carbohydrate: simplifying a complex topic
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet.
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet. I constantly study the research and remain convinced that wholesome forms of carbohydrate are the best choices for both athletes and fitness exercisers for fueling your muscles and promoting good health. In this chapter, I will explain why.
People of all ages and athletic abilities will benefit from nourishing themselves with minimally processed carbohydrate-rich fruits, vegetables, beans, legumes, and whole-grain foods, along with the right balance of protein and healthy fats. But why do some athletes insist they feel better when they stop eating bread, cereal, and pasta? Carolyn, an avid triathlete, raved about how much better she felt after having cut out carbs. I asked, “What were you eating before you made this change?” Her answer indicated the Standard American diet (SAD), with skipped meals, abundant fast foods, and more junk snacks than high-quality meals. No wonder she felt better when she started eating better.
Other reasons for feeling so much better after giving up “carbs” might relate to food sensitivities. When you cut out a lot of foods, you eliminate the one or two items that might create feelings of unwellness. A registered dietitian can help you reach the same level of feeling great by working with you to figure out which foods contribute to the sensitivity.
Some athletes embrace a carb-free diet as a way to curb sugar binges that lead to eating too many carbs. An easier way to reduce carb binges is to prevent extreme hunger. Despite popular belief, carb binges are unlikely caused by being addicted to carbs, but rather caused by the physiological effects of hunger. Refer to chapters 5 (sweet cravings) and 16 (weight management).
The purpose of this chapter is to eliminate this confusion so you can make choices that best promote good health, appropriate weight, and optimal sports performance.
Simple and Complex Carbohydrates
The carbohydrate family includes both simple and complex carbohydrates. The simple carbohydrates are monosaccharides and disaccharides (single- and double-sugar molecules). Glucose, fructose, and galactose are monosaccharides, the simplest sugars, and can be symbolized like this:
The disaccharides can be symbolized like this:
Four common sources of disaccharides are table sugar (sucrose), milk sugar (lactose, a combination of glucose and galactose), corn syrup, and honey.
Table sugar, corn syrup, and honey all contain glucose and fructose but in different amounts.
- Table sugar, upon digestion, breaks apart into 50 percent glucose and 50 percent fructose.
- High-fructose corn syrup (HFCS), commonly used in soft drinks, breaks down to about 55 percent fructose and 45 percent glucose. (HFCS is made using chemical processes that first convert cornstarch to corn syrup and then convert about 55 percent of the glucose in the corn syrup to fructose to make it taste sweeter.)
- Honey contains about 31 percent glucose, 38 percent fructose, 10 percent other sugars, 17 percent water, and 4 percent miscellaneous particles.
Your body eventually converts all monosaccharides and disaccharides to glucose, which travels in the blood (blood glucose) to fuel your muscles and brain.
Fruits and vegetables offer a variety of sugars in differing proportions. Because you absorb different sugars at different rates and by differing pathways, research indicates that consuming a variety of sugars allows for better absorption during exercise. This means that you should read the ingredient label on your sports drink to be sure it offers more than one type of sugar.
Honey has been mistakenly described as being superior to HFCS or refined white sugar. If you prefer honey because of the pleasant taste, fine. But it's not superior in terms of vitamins or performance. Sugar in any form—honey, maple syrup, corn syrup, brown sugar, raw sugar, or agave—offers insignificant nutritional value, and your body digests any type of sugar or carbohydrate into glucose before using it for fuel.
Another type of sugar that is found in many engineered sports foods is maltodextrins, also called glucose polymers. Maltodextrins are chains of about five glucose molecules. Sports drinks sweetened with maltodextrins can provide energy with rapid absorption and less sweetness than regular sugar provides. Sports fuels that use maltodextrins include Hammer Nutrition products.
Complex carbohydrates, such as starch in plant foods and glycogen in muscles, are formed when sugars link together to form long complex chains, similar to a string of hundreds of pearls. They can be symbolized like this:
Plants store extra sugar in the form of starch. For example, corn is sweet when it's young, but it becomes starchy as it gets older. Its extra sugar converts into starch. In contrast to corn and other vegetables, fruits tend to convert starch into sugar as they ripen. A good example is the banana:
- A green banana with some yellow is 80 percent starch and 7 percent sugar.
- A mostly yellow banana is 25 percent starch and 65 percent sugar.
- A spotted and speckled banana is 5 percent starch and 90 percent sugar.
The potatoes, rice, bread, and other starches you eat are digested into glucose and then burned for energy or stored for future use. Humans store extra glucose mostly in the form of muscle glycogen and liver glycogen (but generally not as body fat). This glycogen is readily available for energy during exercise.
Sugars and starches have similar abilities to fuel muscles but different abilities to nourish them with vitamins and minerals:
- The refined carbohydrate in sugary soft drinks provides energy but no vitamins or minerals.
- The highly processed carbohydrate in sports drinks, candies, and gels provides energy but no vitamins or minerals, unless the foods are fortified.
- The natural sugars and unrefined carbohydrate in fruits, vegetables, and whole grains provide energy, vitamins, minerals, fiber, and phytochemicals—the fuel and spark plugs that your body's engine needs to function best.
Protein and the vegetarian
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods.
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods. They may find animal protein hard to digest or believe it is bad for their health, unethical to eat, or erosive to the environment. (Cattle are a source of greenhouse gas that contributes to global warming.) Meatless Mondays (and other days, too) are a good idea for the planet! And a balanced vegetarian diet is indeed a good investment in good health. A plant-based diet tends to have more fiber, less saturated fat, and more phytochemicals—active compounds that bolster the immune system, reduce inflammation, and are health protective.
The trick to eating a balanced vegetarian diet is to make the effort to replace meat with plant proteins. That is, if you eliminate the meatballs from your pasta dinner, add an alternative source of plant-based protein. Do not simply fuel up only on pasta and neglect your protein needs. You can get adequate protein to support your sports program by including kidney beans, chickpeas, hummus, nut butter, tofu, nuts, veggie burgers, edamame, and other forms of plant protein in each meal.
Tofu (soybean curd) and other soy products, such as soy burgers and soy milk, are smart additions to a meat-free diet. They contain a source of high-quality protein that is similar in value to animal protein. Note that a Boca Burger (soy protein) has far less protein than a hamburger, however (refer to table 7.2). Despite popular belief among male athletes, the plant estrogens in soy do not have a feminizing effect, do not reduce testosterone levels, and do not impair fertility (Messina 2010). All athletes can enjoy soy foods in moderation, as with any food, as a health-promoting part of a balanced sports diet.
For lacto-vegetarians (who consume dairy foods), milk and (Greek) yogurt are simple ways to add extra high-quality protein to meals and snacks. Although they have been given a bad rap because they are high in saturated fat, recent studies question whether a connection exits between dairy fat and heart disease and stroke regardless of the milk fat levels (de Oliveira Otto et al. 2018). This controversial topic is worthy of continued research, so until the American Heart Association gives the green light for full-fat dairy foods, a wise plan is to choose mostly reduced-fat dairy foods and balance full-fat choices into an overall healthy eating pattern. That said, blue cheese and other “moldy cheeses” may be a positive addition to the diet regardless of their saturated fat: They support gut bacteria that promote good health (Petyaev and Bashmakov 2012).
Milk, other dairy foods, eggs, and all animal sources of protein contain all the essential amino acids and are often referred to as complete proteins. The protein in soy foods such as tofu, tempeh, edamame, and soy milk are also complete proteins. The protein in rice, beans, pasta, lentils, nuts, fruits, vegetables, and other plant foods are incomplete because they contain low levels of some of the essential amino acids. Therefore, vegetarians must eat a variety of foods to get a variety of amino acids that combine with incomplete proteins to make them complete. Vegetarians who drink milk can easily do this by adding soy milk or dairy products to each meal, for example, combining (soy) milk with oatmeal or sprinkling grated low-fat (soy) cheese on beans. Note that rice and almond milks are not nutritionally equal to soy milk, but rather are very poor protein sources (see chapter 1).
Vegans (strict vegetarians who eat no dairy, eggs, or animal protein) need to consistently eat a variety of foods to optimize their intake of a variety of amino acids over the course of the day. The following combinations work particularly well together; they complement each other by boosting the limiting amino acid:
- Grains plus beans or legumes, such as rice and beans, bread and split-pea soup, tofu and brown rice, corn bread and chili with kidney beans
- Legumes plus seeds, such as chickpeas and tahini (as in hummus), tofu and sesame seeds
- Added soy products (or dairy, if nonvegan), such as cereal and (soy) milk, baked potato and Greek or soy yogurt, hummus wrap with low-fat (soy) cheese
By following these guidelines, vegetarian athletes can consume an adequate amount of complete protein every day. They may, however, lack iron and zinc, minerals found primarily in meats and other animal products. Vegans also need to be sure they get adequate riboflavin, calcium, and vitamin B12, either through a supplement or from carefully selected food sources.
Why carbohydrates are important for active people
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again.
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again. They are not fattening, and you need them to fuel your muscles so that you can enjoy your exercise program.
The average 150-pound (68 kg) man has about 1,800 calories of carbohydrate stored in the liver, muscles, blood, and body fluids in approximately the distribution shown in table 6.2.
The carbohydrate in the muscles is used during exercise. The carbohydrate in the liver is released into the bloodstream to maintain a normal blood glucose level and feed the brain (as well as the muscles). These limited carbohydrate stores influence how long you can enjoy exercising. When your glycogen stores get too low, you hit the wall—that is, you feel overwhelmingly fatigued and yearn to quit. In a research study, cyclists with depleted muscle glycogen stores were able to exercise only 55 minutes to fatigue (as measured by an inability to maintain a specified pedaling speed on a stationary bicycle), as compared with more than twice as long—about 120 minutes—when they were carbohydrate loaded (Green et al. 2007). Food works!
In comparison to the approximately 1,800 calories of stored carbohydrate, the average lean 150-pound (68 kg) man also has 60,000 to 100,000 calories of stored fat—enough to run hundreds of miles. During low-level exercise such as walking, the muscles burn primarily fat for energy. During light to moderate aerobic exercise, such as jogging, stored fat provides 50 to 60 percent of the fuel. When you exercise hard, as in sprinting, racing, lifting weights, or other intense exercise, you rely primarily on glycogen stores. Unfortunately, for competitive athletes, fat cannot be used exclusively as fuel because the muscles need a certain amount of carbohydrate to function well at high intensities, such as a surge up a hill or a sprint to the finish. Fitness exercisers can get away with a lower carbohydrate intake than elite athletes who push themselves to exhaustion can.
Biochemical changes that occur during training influence the amount of glycogen you can store in your muscles. The figures that follow indicate that well-trained muscles store 20 to 50 percent more glycogen than untrained muscles do (Costill et al. 1981; Sherman et al. 1981). This change enhances endurance capacity and is one reason a novice runner can't just load up on carbohydrate and run a top-quality marathon (table 6.3).
Because of the unfounded fears that carbohydrate is fattening or the belief that you need a high-protein diet to build muscle or a high-fat diet for endurance, many athletes today are skimping on carbohydrate foods. Some go on the paleo diet or keto diet; others go gluten free. The resulting low-carbohydrate intake can potentially hurt performance; it contrasts sharply with the diet of 2.5 to 4.5 grams of carbohydrate per pound of body weight (5 to 10 g/kg)—or 55 to 65 percent carbohydrate—recommended by most exercise and health professionals for people who train for one to three hours a day.
A case in point is ice hockey, an incredibly intense sport that relies on both muscular strength and power. During a game, carbohydrate is the primary fuel, and muscle carbohydrate (glycogen) stores decline between 38 and 88 percent. Muscle glycogen depletion relates closely to muscular fatigue. A motion analysis of elite ice hockey teams showed that the players with a high-carbohydrate (60 percent) diet skated not only 30 percent more distance but also faster than the players who ate their standard low-carbohydrate (40 percent) diet. In the final period of the game, which often determines whether a team wins or loses, the high-carbohydrate group skated 11 percent more distance than they did in the first period; the low-carbohydrate group skated 14 percent less. The researchers reached the following conclusions (Ackermark et al. 1996):
- Low muscle glycogen stores at the start of the game can jeopardize performance at the end of the game.
- Three days between games (with training on two of those days) plus a low-carbohydrate (40 percent) diet does not replace normal muscle glycogen stores (the players in the high-carbohydrate group had 45 percent more glycogen).
- The differences in performance between the well-fueled players and those who ate inadequate carbohydrate were most evident in the last period of the game.
Whether your sport is ice hockey, soccer, rugby, football, basketball, or any intense sport, remember to eat responsibly. Make carbohydrate the foundation of each meal and protein the accompaniment.
After exercise, it is important to consume carbohydrate to replenish muscle glycogen stores. In a landmark study, exercise physiologist J. Bergstrom and his colleagues (1967) compared the rate at which muscle glycogen was replaced in subjects who exercised to exhaustion and then ate either a high-protein, high-fat diet, or a high-carbohydrate diet. The subjects on the high-protein, high-fat diet (similar to an Atkins or other high-protein, low-carbohydrate diet with abundant eggs, chicken, beef, cheese, and nuts) remained glycogen depleted for five days (figure 6.1). The subjects on the high-carbohydrate diet totally replenished their muscle glycogen in two days. This result shows that protein and fat aren't stored as muscle glycogen and that carbohydrate is important for replacing depleted glycogen stores. Other research suggests that three sets of biceps curls (8 to 10 repetitions per set) reduce muscle glycogen by 35 percent (Martin, Armstrong, and Rodriquez 2005). With repeated days of low carbohydrate and high repetitions, the muscles of bodybuilders and marathon runners can soon become depleted. Hence, every athlete should eat meals in which two-thirds of the plate is dedicated to wholesome carbohydrates (grains, vegetables, fruits) and one-third to protein.
Carbohydrate: simplifying a complex topic
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet.
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet. I constantly study the research and remain convinced that wholesome forms of carbohydrate are the best choices for both athletes and fitness exercisers for fueling your muscles and promoting good health. In this chapter, I will explain why.
People of all ages and athletic abilities will benefit from nourishing themselves with minimally processed carbohydrate-rich fruits, vegetables, beans, legumes, and whole-grain foods, along with the right balance of protein and healthy fats. But why do some athletes insist they feel better when they stop eating bread, cereal, and pasta? Carolyn, an avid triathlete, raved about how much better she felt after having cut out carbs. I asked, “What were you eating before you made this change?” Her answer indicated the Standard American diet (SAD), with skipped meals, abundant fast foods, and more junk snacks than high-quality meals. No wonder she felt better when she started eating better.
Other reasons for feeling so much better after giving up “carbs” might relate to food sensitivities. When you cut out a lot of foods, you eliminate the one or two items that might create feelings of unwellness. A registered dietitian can help you reach the same level of feeling great by working with you to figure out which foods contribute to the sensitivity.
Some athletes embrace a carb-free diet as a way to curb sugar binges that lead to eating too many carbs. An easier way to reduce carb binges is to prevent extreme hunger. Despite popular belief, carb binges are unlikely caused by being addicted to carbs, but rather caused by the physiological effects of hunger. Refer to chapters 5 (sweet cravings) and 16 (weight management).
The purpose of this chapter is to eliminate this confusion so you can make choices that best promote good health, appropriate weight, and optimal sports performance.
Simple and Complex Carbohydrates
The carbohydrate family includes both simple and complex carbohydrates. The simple carbohydrates are monosaccharides and disaccharides (single- and double-sugar molecules). Glucose, fructose, and galactose are monosaccharides, the simplest sugars, and can be symbolized like this:
The disaccharides can be symbolized like this:
Four common sources of disaccharides are table sugar (sucrose), milk sugar (lactose, a combination of glucose and galactose), corn syrup, and honey.
Table sugar, corn syrup, and honey all contain glucose and fructose but in different amounts.
- Table sugar, upon digestion, breaks apart into 50 percent glucose and 50 percent fructose.
- High-fructose corn syrup (HFCS), commonly used in soft drinks, breaks down to about 55 percent fructose and 45 percent glucose. (HFCS is made using chemical processes that first convert cornstarch to corn syrup and then convert about 55 percent of the glucose in the corn syrup to fructose to make it taste sweeter.)
- Honey contains about 31 percent glucose, 38 percent fructose, 10 percent other sugars, 17 percent water, and 4 percent miscellaneous particles.
Your body eventually converts all monosaccharides and disaccharides to glucose, which travels in the blood (blood glucose) to fuel your muscles and brain.
Fruits and vegetables offer a variety of sugars in differing proportions. Because you absorb different sugars at different rates and by differing pathways, research indicates that consuming a variety of sugars allows for better absorption during exercise. This means that you should read the ingredient label on your sports drink to be sure it offers more than one type of sugar.
Honey has been mistakenly described as being superior to HFCS or refined white sugar. If you prefer honey because of the pleasant taste, fine. But it's not superior in terms of vitamins or performance. Sugar in any form—honey, maple syrup, corn syrup, brown sugar, raw sugar, or agave—offers insignificant nutritional value, and your body digests any type of sugar or carbohydrate into glucose before using it for fuel.
Another type of sugar that is found in many engineered sports foods is maltodextrins, also called glucose polymers. Maltodextrins are chains of about five glucose molecules. Sports drinks sweetened with maltodextrins can provide energy with rapid absorption and less sweetness than regular sugar provides. Sports fuels that use maltodextrins include Hammer Nutrition products.
Complex carbohydrates, such as starch in plant foods and glycogen in muscles, are formed when sugars link together to form long complex chains, similar to a string of hundreds of pearls. They can be symbolized like this:
Plants store extra sugar in the form of starch. For example, corn is sweet when it's young, but it becomes starchy as it gets older. Its extra sugar converts into starch. In contrast to corn and other vegetables, fruits tend to convert starch into sugar as they ripen. A good example is the banana:
- A green banana with some yellow is 80 percent starch and 7 percent sugar.
- A mostly yellow banana is 25 percent starch and 65 percent sugar.
- A spotted and speckled banana is 5 percent starch and 90 percent sugar.
The potatoes, rice, bread, and other starches you eat are digested into glucose and then burned for energy or stored for future use. Humans store extra glucose mostly in the form of muscle glycogen and liver glycogen (but generally not as body fat). This glycogen is readily available for energy during exercise.
Sugars and starches have similar abilities to fuel muscles but different abilities to nourish them with vitamins and minerals:
- The refined carbohydrate in sugary soft drinks provides energy but no vitamins or minerals.
- The highly processed carbohydrate in sports drinks, candies, and gels provides energy but no vitamins or minerals, unless the foods are fortified.
- The natural sugars and unrefined carbohydrate in fruits, vegetables, and whole grains provide energy, vitamins, minerals, fiber, and phytochemicals—the fuel and spark plugs that your body's engine needs to function best.
Protein and the vegetarian
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods.
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods. They may find animal protein hard to digest or believe it is bad for their health, unethical to eat, or erosive to the environment. (Cattle are a source of greenhouse gas that contributes to global warming.) Meatless Mondays (and other days, too) are a good idea for the planet! And a balanced vegetarian diet is indeed a good investment in good health. A plant-based diet tends to have more fiber, less saturated fat, and more phytochemicals—active compounds that bolster the immune system, reduce inflammation, and are health protective.
The trick to eating a balanced vegetarian diet is to make the effort to replace meat with plant proteins. That is, if you eliminate the meatballs from your pasta dinner, add an alternative source of plant-based protein. Do not simply fuel up only on pasta and neglect your protein needs. You can get adequate protein to support your sports program by including kidney beans, chickpeas, hummus, nut butter, tofu, nuts, veggie burgers, edamame, and other forms of plant protein in each meal.
Tofu (soybean curd) and other soy products, such as soy burgers and soy milk, are smart additions to a meat-free diet. They contain a source of high-quality protein that is similar in value to animal protein. Note that a Boca Burger (soy protein) has far less protein than a hamburger, however (refer to table 7.2). Despite popular belief among male athletes, the plant estrogens in soy do not have a feminizing effect, do not reduce testosterone levels, and do not impair fertility (Messina 2010). All athletes can enjoy soy foods in moderation, as with any food, as a health-promoting part of a balanced sports diet.
For lacto-vegetarians (who consume dairy foods), milk and (Greek) yogurt are simple ways to add extra high-quality protein to meals and snacks. Although they have been given a bad rap because they are high in saturated fat, recent studies question whether a connection exits between dairy fat and heart disease and stroke regardless of the milk fat levels (de Oliveira Otto et al. 2018). This controversial topic is worthy of continued research, so until the American Heart Association gives the green light for full-fat dairy foods, a wise plan is to choose mostly reduced-fat dairy foods and balance full-fat choices into an overall healthy eating pattern. That said, blue cheese and other “moldy cheeses” may be a positive addition to the diet regardless of their saturated fat: They support gut bacteria that promote good health (Petyaev and Bashmakov 2012).
Milk, other dairy foods, eggs, and all animal sources of protein contain all the essential amino acids and are often referred to as complete proteins. The protein in soy foods such as tofu, tempeh, edamame, and soy milk are also complete proteins. The protein in rice, beans, pasta, lentils, nuts, fruits, vegetables, and other plant foods are incomplete because they contain low levels of some of the essential amino acids. Therefore, vegetarians must eat a variety of foods to get a variety of amino acids that combine with incomplete proteins to make them complete. Vegetarians who drink milk can easily do this by adding soy milk or dairy products to each meal, for example, combining (soy) milk with oatmeal or sprinkling grated low-fat (soy) cheese on beans. Note that rice and almond milks are not nutritionally equal to soy milk, but rather are very poor protein sources (see chapter 1).
Vegans (strict vegetarians who eat no dairy, eggs, or animal protein) need to consistently eat a variety of foods to optimize their intake of a variety of amino acids over the course of the day. The following combinations work particularly well together; they complement each other by boosting the limiting amino acid:
- Grains plus beans or legumes, such as rice and beans, bread and split-pea soup, tofu and brown rice, corn bread and chili with kidney beans
- Legumes plus seeds, such as chickpeas and tahini (as in hummus), tofu and sesame seeds
- Added soy products (or dairy, if nonvegan), such as cereal and (soy) milk, baked potato and Greek or soy yogurt, hummus wrap with low-fat (soy) cheese
By following these guidelines, vegetarian athletes can consume an adequate amount of complete protein every day. They may, however, lack iron and zinc, minerals found primarily in meats and other animal products. Vegans also need to be sure they get adequate riboflavin, calcium, and vitamin B12, either through a supplement or from carefully selected food sources.
Why carbohydrates are important for active people
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again.
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again. They are not fattening, and you need them to fuel your muscles so that you can enjoy your exercise program.
The average 150-pound (68 kg) man has about 1,800 calories of carbohydrate stored in the liver, muscles, blood, and body fluids in approximately the distribution shown in table 6.2.
The carbohydrate in the muscles is used during exercise. The carbohydrate in the liver is released into the bloodstream to maintain a normal blood glucose level and feed the brain (as well as the muscles). These limited carbohydrate stores influence how long you can enjoy exercising. When your glycogen stores get too low, you hit the wall—that is, you feel overwhelmingly fatigued and yearn to quit. In a research study, cyclists with depleted muscle glycogen stores were able to exercise only 55 minutes to fatigue (as measured by an inability to maintain a specified pedaling speed on a stationary bicycle), as compared with more than twice as long—about 120 minutes—when they were carbohydrate loaded (Green et al. 2007). Food works!
In comparison to the approximately 1,800 calories of stored carbohydrate, the average lean 150-pound (68 kg) man also has 60,000 to 100,000 calories of stored fat—enough to run hundreds of miles. During low-level exercise such as walking, the muscles burn primarily fat for energy. During light to moderate aerobic exercise, such as jogging, stored fat provides 50 to 60 percent of the fuel. When you exercise hard, as in sprinting, racing, lifting weights, or other intense exercise, you rely primarily on glycogen stores. Unfortunately, for competitive athletes, fat cannot be used exclusively as fuel because the muscles need a certain amount of carbohydrate to function well at high intensities, such as a surge up a hill or a sprint to the finish. Fitness exercisers can get away with a lower carbohydrate intake than elite athletes who push themselves to exhaustion can.
Biochemical changes that occur during training influence the amount of glycogen you can store in your muscles. The figures that follow indicate that well-trained muscles store 20 to 50 percent more glycogen than untrained muscles do (Costill et al. 1981; Sherman et al. 1981). This change enhances endurance capacity and is one reason a novice runner can't just load up on carbohydrate and run a top-quality marathon (table 6.3).
Because of the unfounded fears that carbohydrate is fattening or the belief that you need a high-protein diet to build muscle or a high-fat diet for endurance, many athletes today are skimping on carbohydrate foods. Some go on the paleo diet or keto diet; others go gluten free. The resulting low-carbohydrate intake can potentially hurt performance; it contrasts sharply with the diet of 2.5 to 4.5 grams of carbohydrate per pound of body weight (5 to 10 g/kg)—or 55 to 65 percent carbohydrate—recommended by most exercise and health professionals for people who train for one to three hours a day.
A case in point is ice hockey, an incredibly intense sport that relies on both muscular strength and power. During a game, carbohydrate is the primary fuel, and muscle carbohydrate (glycogen) stores decline between 38 and 88 percent. Muscle glycogen depletion relates closely to muscular fatigue. A motion analysis of elite ice hockey teams showed that the players with a high-carbohydrate (60 percent) diet skated not only 30 percent more distance but also faster than the players who ate their standard low-carbohydrate (40 percent) diet. In the final period of the game, which often determines whether a team wins or loses, the high-carbohydrate group skated 11 percent more distance than they did in the first period; the low-carbohydrate group skated 14 percent less. The researchers reached the following conclusions (Ackermark et al. 1996):
- Low muscle glycogen stores at the start of the game can jeopardize performance at the end of the game.
- Three days between games (with training on two of those days) plus a low-carbohydrate (40 percent) diet does not replace normal muscle glycogen stores (the players in the high-carbohydrate group had 45 percent more glycogen).
- The differences in performance between the well-fueled players and those who ate inadequate carbohydrate were most evident in the last period of the game.
Whether your sport is ice hockey, soccer, rugby, football, basketball, or any intense sport, remember to eat responsibly. Make carbohydrate the foundation of each meal and protein the accompaniment.
After exercise, it is important to consume carbohydrate to replenish muscle glycogen stores. In a landmark study, exercise physiologist J. Bergstrom and his colleagues (1967) compared the rate at which muscle glycogen was replaced in subjects who exercised to exhaustion and then ate either a high-protein, high-fat diet, or a high-carbohydrate diet. The subjects on the high-protein, high-fat diet (similar to an Atkins or other high-protein, low-carbohydrate diet with abundant eggs, chicken, beef, cheese, and nuts) remained glycogen depleted for five days (figure 6.1). The subjects on the high-carbohydrate diet totally replenished their muscle glycogen in two days. This result shows that protein and fat aren't stored as muscle glycogen and that carbohydrate is important for replacing depleted glycogen stores. Other research suggests that three sets of biceps curls (8 to 10 repetitions per set) reduce muscle glycogen by 35 percent (Martin, Armstrong, and Rodriquez 2005). With repeated days of low carbohydrate and high repetitions, the muscles of bodybuilders and marathon runners can soon become depleted. Hence, every athlete should eat meals in which two-thirds of the plate is dedicated to wholesome carbohydrates (grains, vegetables, fruits) and one-third to protein.
Carbohydrate: simplifying a complex topic
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet.
In this day and age of high-protein diets (to build muscle) and high-fat ketogenic diets (to lose weight), as well as chatter about training low (with depleted carbohydrate stores), confusion abounds about the role of carbohydrates in a sports diet. I constantly study the research and remain convinced that wholesome forms of carbohydrate are the best choices for both athletes and fitness exercisers for fueling your muscles and promoting good health. In this chapter, I will explain why.
People of all ages and athletic abilities will benefit from nourishing themselves with minimally processed carbohydrate-rich fruits, vegetables, beans, legumes, and whole-grain foods, along with the right balance of protein and healthy fats. But why do some athletes insist they feel better when they stop eating bread, cereal, and pasta? Carolyn, an avid triathlete, raved about how much better she felt after having cut out carbs. I asked, “What were you eating before you made this change?” Her answer indicated the Standard American diet (SAD), with skipped meals, abundant fast foods, and more junk snacks than high-quality meals. No wonder she felt better when she started eating better.
Other reasons for feeling so much better after giving up “carbs” might relate to food sensitivities. When you cut out a lot of foods, you eliminate the one or two items that might create feelings of unwellness. A registered dietitian can help you reach the same level of feeling great by working with you to figure out which foods contribute to the sensitivity.
Some athletes embrace a carb-free diet as a way to curb sugar binges that lead to eating too many carbs. An easier way to reduce carb binges is to prevent extreme hunger. Despite popular belief, carb binges are unlikely caused by being addicted to carbs, but rather caused by the physiological effects of hunger. Refer to chapters 5 (sweet cravings) and 16 (weight management).
The purpose of this chapter is to eliminate this confusion so you can make choices that best promote good health, appropriate weight, and optimal sports performance.
Simple and Complex Carbohydrates
The carbohydrate family includes both simple and complex carbohydrates. The simple carbohydrates are monosaccharides and disaccharides (single- and double-sugar molecules). Glucose, fructose, and galactose are monosaccharides, the simplest sugars, and can be symbolized like this:
The disaccharides can be symbolized like this:
Four common sources of disaccharides are table sugar (sucrose), milk sugar (lactose, a combination of glucose and galactose), corn syrup, and honey.
Table sugar, corn syrup, and honey all contain glucose and fructose but in different amounts.
- Table sugar, upon digestion, breaks apart into 50 percent glucose and 50 percent fructose.
- High-fructose corn syrup (HFCS), commonly used in soft drinks, breaks down to about 55 percent fructose and 45 percent glucose. (HFCS is made using chemical processes that first convert cornstarch to corn syrup and then convert about 55 percent of the glucose in the corn syrup to fructose to make it taste sweeter.)
- Honey contains about 31 percent glucose, 38 percent fructose, 10 percent other sugars, 17 percent water, and 4 percent miscellaneous particles.
Your body eventually converts all monosaccharides and disaccharides to glucose, which travels in the blood (blood glucose) to fuel your muscles and brain.
Fruits and vegetables offer a variety of sugars in differing proportions. Because you absorb different sugars at different rates and by differing pathways, research indicates that consuming a variety of sugars allows for better absorption during exercise. This means that you should read the ingredient label on your sports drink to be sure it offers more than one type of sugar.
Honey has been mistakenly described as being superior to HFCS or refined white sugar. If you prefer honey because of the pleasant taste, fine. But it's not superior in terms of vitamins or performance. Sugar in any form—honey, maple syrup, corn syrup, brown sugar, raw sugar, or agave—offers insignificant nutritional value, and your body digests any type of sugar or carbohydrate into glucose before using it for fuel.
Another type of sugar that is found in many engineered sports foods is maltodextrins, also called glucose polymers. Maltodextrins are chains of about five glucose molecules. Sports drinks sweetened with maltodextrins can provide energy with rapid absorption and less sweetness than regular sugar provides. Sports fuels that use maltodextrins include Hammer Nutrition products.
Complex carbohydrates, such as starch in plant foods and glycogen in muscles, are formed when sugars link together to form long complex chains, similar to a string of hundreds of pearls. They can be symbolized like this:
Plants store extra sugar in the form of starch. For example, corn is sweet when it's young, but it becomes starchy as it gets older. Its extra sugar converts into starch. In contrast to corn and other vegetables, fruits tend to convert starch into sugar as they ripen. A good example is the banana:
- A green banana with some yellow is 80 percent starch and 7 percent sugar.
- A mostly yellow banana is 25 percent starch and 65 percent sugar.
- A spotted and speckled banana is 5 percent starch and 90 percent sugar.
The potatoes, rice, bread, and other starches you eat are digested into glucose and then burned for energy or stored for future use. Humans store extra glucose mostly in the form of muscle glycogen and liver glycogen (but generally not as body fat). This glycogen is readily available for energy during exercise.
Sugars and starches have similar abilities to fuel muscles but different abilities to nourish them with vitamins and minerals:
- The refined carbohydrate in sugary soft drinks provides energy but no vitamins or minerals.
- The highly processed carbohydrate in sports drinks, candies, and gels provides energy but no vitamins or minerals, unless the foods are fortified.
- The natural sugars and unrefined carbohydrate in fruits, vegetables, and whole grains provide energy, vitamins, minerals, fiber, and phytochemicals—the fuel and spark plugs that your body's engine needs to function best.
Protein and the vegetarian
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods.
Many active people do not eat animal protein. Some just eat no red meat; others eat no red meat, chicken, fish, eggs, or dairy foods. They may find animal protein hard to digest or believe it is bad for their health, unethical to eat, or erosive to the environment. (Cattle are a source of greenhouse gas that contributes to global warming.) Meatless Mondays (and other days, too) are a good idea for the planet! And a balanced vegetarian diet is indeed a good investment in good health. A plant-based diet tends to have more fiber, less saturated fat, and more phytochemicals—active compounds that bolster the immune system, reduce inflammation, and are health protective.
The trick to eating a balanced vegetarian diet is to make the effort to replace meat with plant proteins. That is, if you eliminate the meatballs from your pasta dinner, add an alternative source of plant-based protein. Do not simply fuel up only on pasta and neglect your protein needs. You can get adequate protein to support your sports program by including kidney beans, chickpeas, hummus, nut butter, tofu, nuts, veggie burgers, edamame, and other forms of plant protein in each meal.
Tofu (soybean curd) and other soy products, such as soy burgers and soy milk, are smart additions to a meat-free diet. They contain a source of high-quality protein that is similar in value to animal protein. Note that a Boca Burger (soy protein) has far less protein than a hamburger, however (refer to table 7.2). Despite popular belief among male athletes, the plant estrogens in soy do not have a feminizing effect, do not reduce testosterone levels, and do not impair fertility (Messina 2010). All athletes can enjoy soy foods in moderation, as with any food, as a health-promoting part of a balanced sports diet.
For lacto-vegetarians (who consume dairy foods), milk and (Greek) yogurt are simple ways to add extra high-quality protein to meals and snacks. Although they have been given a bad rap because they are high in saturated fat, recent studies question whether a connection exits between dairy fat and heart disease and stroke regardless of the milk fat levels (de Oliveira Otto et al. 2018). This controversial topic is worthy of continued research, so until the American Heart Association gives the green light for full-fat dairy foods, a wise plan is to choose mostly reduced-fat dairy foods and balance full-fat choices into an overall healthy eating pattern. That said, blue cheese and other “moldy cheeses” may be a positive addition to the diet regardless of their saturated fat: They support gut bacteria that promote good health (Petyaev and Bashmakov 2012).
Milk, other dairy foods, eggs, and all animal sources of protein contain all the essential amino acids and are often referred to as complete proteins. The protein in soy foods such as tofu, tempeh, edamame, and soy milk are also complete proteins. The protein in rice, beans, pasta, lentils, nuts, fruits, vegetables, and other plant foods are incomplete because they contain low levels of some of the essential amino acids. Therefore, vegetarians must eat a variety of foods to get a variety of amino acids that combine with incomplete proteins to make them complete. Vegetarians who drink milk can easily do this by adding soy milk or dairy products to each meal, for example, combining (soy) milk with oatmeal or sprinkling grated low-fat (soy) cheese on beans. Note that rice and almond milks are not nutritionally equal to soy milk, but rather are very poor protein sources (see chapter 1).
Vegans (strict vegetarians who eat no dairy, eggs, or animal protein) need to consistently eat a variety of foods to optimize their intake of a variety of amino acids over the course of the day. The following combinations work particularly well together; they complement each other by boosting the limiting amino acid:
- Grains plus beans or legumes, such as rice and beans, bread and split-pea soup, tofu and brown rice, corn bread and chili with kidney beans
- Legumes plus seeds, such as chickpeas and tahini (as in hummus), tofu and sesame seeds
- Added soy products (or dairy, if nonvegan), such as cereal and (soy) milk, baked potato and Greek or soy yogurt, hummus wrap with low-fat (soy) cheese
By following these guidelines, vegetarian athletes can consume an adequate amount of complete protein every day. They may, however, lack iron and zinc, minerals found primarily in meats and other animal products. Vegans also need to be sure they get adequate riboflavin, calcium, and vitamin B12, either through a supplement or from carefully selected food sources.
Why carbohydrates are important for active people
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again.
If you are trying to stay away from forms of carbohydrate such as bagels, potatoes, and breads because you mistakenly believe carbohydrate to be fattening, think again. They are not fattening, and you need them to fuel your muscles so that you can enjoy your exercise program.
The average 150-pound (68 kg) man has about 1,800 calories of carbohydrate stored in the liver, muscles, blood, and body fluids in approximately the distribution shown in table 6.2.
The carbohydrate in the muscles is used during exercise. The carbohydrate in the liver is released into the bloodstream to maintain a normal blood glucose level and feed the brain (as well as the muscles). These limited carbohydrate stores influence how long you can enjoy exercising. When your glycogen stores get too low, you hit the wall—that is, you feel overwhelmingly fatigued and yearn to quit. In a research study, cyclists with depleted muscle glycogen stores were able to exercise only 55 minutes to fatigue (as measured by an inability to maintain a specified pedaling speed on a stationary bicycle), as compared with more than twice as long—about 120 minutes—when they were carbohydrate loaded (Green et al. 2007). Food works!
In comparison to the approximately 1,800 calories of stored carbohydrate, the average lean 150-pound (68 kg) man also has 60,000 to 100,000 calories of stored fat—enough to run hundreds of miles. During low-level exercise such as walking, the muscles burn primarily fat for energy. During light to moderate aerobic exercise, such as jogging, stored fat provides 50 to 60 percent of the fuel. When you exercise hard, as in sprinting, racing, lifting weights, or other intense exercise, you rely primarily on glycogen stores. Unfortunately, for competitive athletes, fat cannot be used exclusively as fuel because the muscles need a certain amount of carbohydrate to function well at high intensities, such as a surge up a hill or a sprint to the finish. Fitness exercisers can get away with a lower carbohydrate intake than elite athletes who push themselves to exhaustion can.
Biochemical changes that occur during training influence the amount of glycogen you can store in your muscles. The figures that follow indicate that well-trained muscles store 20 to 50 percent more glycogen than untrained muscles do (Costill et al. 1981; Sherman et al. 1981). This change enhances endurance capacity and is one reason a novice runner can't just load up on carbohydrate and run a top-quality marathon (table 6.3).
Because of the unfounded fears that carbohydrate is fattening or the belief that you need a high-protein diet to build muscle or a high-fat diet for endurance, many athletes today are skimping on carbohydrate foods. Some go on the paleo diet or keto diet; others go gluten free. The resulting low-carbohydrate intake can potentially hurt performance; it contrasts sharply with the diet of 2.5 to 4.5 grams of carbohydrate per pound of body weight (5 to 10 g/kg)—or 55 to 65 percent carbohydrate—recommended by most exercise and health professionals for people who train for one to three hours a day.
A case in point is ice hockey, an incredibly intense sport that relies on both muscular strength and power. During a game, carbohydrate is the primary fuel, and muscle carbohydrate (glycogen) stores decline between 38 and 88 percent. Muscle glycogen depletion relates closely to muscular fatigue. A motion analysis of elite ice hockey teams showed that the players with a high-carbohydrate (60 percent) diet skated not only 30 percent more distance but also faster than the players who ate their standard low-carbohydrate (40 percent) diet. In the final period of the game, which often determines whether a team wins or loses, the high-carbohydrate group skated 11 percent more distance than they did in the first period; the low-carbohydrate group skated 14 percent less. The researchers reached the following conclusions (Ackermark et al. 1996):
- Low muscle glycogen stores at the start of the game can jeopardize performance at the end of the game.
- Three days between games (with training on two of those days) plus a low-carbohydrate (40 percent) diet does not replace normal muscle glycogen stores (the players in the high-carbohydrate group had 45 percent more glycogen).
- The differences in performance between the well-fueled players and those who ate inadequate carbohydrate were most evident in the last period of the game.
Whether your sport is ice hockey, soccer, rugby, football, basketball, or any intense sport, remember to eat responsibly. Make carbohydrate the foundation of each meal and protein the accompaniment.
After exercise, it is important to consume carbohydrate to replenish muscle glycogen stores. In a landmark study, exercise physiologist J. Bergstrom and his colleagues (1967) compared the rate at which muscle glycogen was replaced in subjects who exercised to exhaustion and then ate either a high-protein, high-fat diet, or a high-carbohydrate diet. The subjects on the high-protein, high-fat diet (similar to an Atkins or other high-protein, low-carbohydrate diet with abundant eggs, chicken, beef, cheese, and nuts) remained glycogen depleted for five days (figure 6.1). The subjects on the high-carbohydrate diet totally replenished their muscle glycogen in two days. This result shows that protein and fat aren't stored as muscle glycogen and that carbohydrate is important for replacing depleted glycogen stores. Other research suggests that three sets of biceps curls (8 to 10 repetitions per set) reduce muscle glycogen by 35 percent (Martin, Armstrong, and Rodriquez 2005). With repeated days of low carbohydrate and high repetitions, the muscles of bodybuilders and marathon runners can soon become depleted. Hence, every athlete should eat meals in which two-thirds of the plate is dedicated to wholesome carbohydrates (grains, vegetables, fruits) and one-third to protein.
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