Chapter 15Focus on nutritionTypical diet vs. recommended dietRecommended caloric intake for healthy persons in the United StatesCaloric intake for athletesCarbohydratesSimple and complex carbohydratesRecommended carbohydrate intake before, during, and after a competitionFactors that affect protein metabolism during exerciseFat intakeVitamin supplementsIron deficiencyIron supplementsThe American College of Sports Medicine’s recommendations regarding fluid intake before, during, and after exercise.Desired characteristics of pre-exercise mealsChapter 15Nutrition for Fitness and AthleticsFocus on nutrition•Sports nutrition is an area in which fads often obscure scientifically valid information.•Performance can deteriorate rapidly if diet is less than optimal•The best diet for one athlete may not be the best for another.Visit:Nutrition Navigator at http://navigator.tufts.eduFood and Nutrition Information Center at www.nal.usda.gov/fnic/American Dietetic Association at www.eatright.orgTypical diet vs. recommended dietTypical:•Carbohydrate–46%•Protein–12%•Fat–42%Recommended:•Carbohydrate–55 to 58%•Protein–12 to 15%•Fat–25 to 30%Recommended caloric intake for healthy persons in the United StatesCaloric intake for athletes•Athletes in heavy training often consume 4000 to 7000 calories a day.•If athletes eat less than they need to meet their energy demands, they will burn body tissues to make up the deficit.Carbohydrates•Contribute to energy production in exercise in the form of blood glucose and stored muscle glycogen•Manipulation of carbohydrate intake and exercise can result in larger than normal store of muscle glycogen and increased endurance•Fat produces more than twice as much energy per gram, but requires more oxygen for each calorie. Carbs offer an advantage of about 7.5%.Simple and complex carbohydrates•Complex carbohydrates—combination of three or more glucose molecules•Simple carbohydrates—one or two sugar molecules joined together–Monosaccharides—glucose, fructose, galactose–Disaccharides—sucrose, lactose, maltose•Only 10% of total caloric intake should come from simple sugarsRecommended carbohydrate intake before, during, and after a competition•Before–should be based on the athlete’s experiments during training•During–take in 25 to 30 grams of carbohydrate (100 to 200 kilocalories) every half hour•After–take in 100 grams of carbohydrate (400 kilocalories) within 15 to 30 minutes of exercise and additional 100-gram feeding every two to four hours thereafterFactors that affect protein metabolism during exercise–Mode of exercise–Frequency of exercise–Intensity of exercise–Duration of exercise–Training status–Quality of proteinFat intake•At beginning of exercise, circulating level of free fatty acids decreases.•After a few minutes of continuous exercise, fatty acids stored in adipose tissue mobilize, increasing circulation of free fatty acids.•Endurance training improves ability to metabolize fats.•Enhanced ability to metabolize fats during submaximal exercise may result in sparing of carbohydrate stores and thus increase duration of activity.Vitamin supplements•If the diet is sound, supplementary vitamins are not needed. Eating larger amounts of food as daily workout levels increase usually provides the needed increase in vitamins.Visit Vitamins and Minerals at www.foundhealth.com/vitaminsIron deficiency•Sports anemia is anemia that occurs in response to heavy endurance training •Three stages of iron deficiency1. Prelatent iron deficiency2. Latent iron deficiency3. Frank anemiaIron supplements•A diet high in iron sources should prevent iron deficiency, but the following may require supplementation:–Male and female endurance athletes–Adolescent athletes–Athletes who lose weight for competition–Vegetarian athletes•Never give iron supplements without medical supervision–Can induce deficiencies of trace minerals–Can produce an iron overload (hemochromatosis)The American College of Sports Medicine’s recommendations regarding fluid intake before, during, and after exercise.1. Drink adequate fluids during the 24-hours before an event.2. Drink about 17 ounces about two hours before exercise.3. During exercise, consume enough fluids to replace water lost through sweating.4. Fluids should be cooler than ambient temperature, flavored, and in containers that make it easy to drink enough without disrupting exercise.5. For events lasting over an hour, fluids should contain proper amounts of carbohydrates and electrolytes.6. During intense exercise lasting more than one hour, drink fluids containing 4 to 8 percent carbohydrates.7. For exercise lasting more than an hour, sodium should be included in the rehydration fluid.Desired characteristics of pre-exercise meals•Have sufficient fluid to maintain hydration•Be low in fat and fiber •Be high in carbohydrate•Be moderate in protein•Be composed of food familiar to the