Nutrition for Exercise & Sport

1. Nutrition for Exercise & Sport Exercise Physiology McArdle, Katch, Katch: Chapter 3 (Part 2)

2. Overview • Nutrient Consumption: Fit & Non-fit • Dietary Reference Intakes • Calorie and Macronutrient Needs • Pre workout (competition) Meal • Water • Carbohydrate • Fat • Protein • Nutrient Timing for Resistance Training

3. Nutrient Consumption: Fit & Unfit • Active people do not require additional nutrients beyond those obtained in a nutritionally well balanced diet. • What physically fit eat compared to unfit. • Small differences in energy intake (low vs high) • Higher dietary fiber & lower cholesterol intakes • Diets more closely approach recommendations • Sound human nutrition represents sound nutrition for athletes.

4. Nutrient Consumption: Fit & Unfit • Most obvious distinction in nutrient needs between active and inactive is moretotal calories. • Volume of physical activity determines energy intake requirements • Relatively high caloric intakes of physically active usually increases protein, vitamin, and mineral nutrients intake above recommended, • Percentage of calories from energy nutrients should remain in normal ranges.

5. Dietary Reference Intakes • Dietary Reference Intakes (DRIs) is an umbrella term encompassing an array of standards: the RDAs, Estimated Average Requirements (EARs), Adequate Intakes (AIs), and tolerable Upper intake Levels(UL). • DRIs differ from predecessor RDAs by focusing on promoting health maintenance and risk-reduction for nutrient-related disease rather than preventing deficiency-related diseases.

6. Dietary Reference Intakes • EAR is average level of daily nutrient intake sufficient to meet requirements of ½ healthy people in given age/gender group. • RDA is average daily nutrient to meet requirements of nearly all people in given age/gender group.

7. Dietary Reference Intakes • Adequate intake (AI)provides a nutritional goal when no RDA exists. • Tolerable upper intake level (UL) is highest average daily nutrient intake likely to pose no risk or adverse health effects to most age/gender group.

8. My Pyramid Replaces Food Guide • My Pyramid replaces Food Guide Pyramid to provide food intake guidance based on age, sex, and level of daily exercise. • Recommend consuming between 45% and 65% of total calories from CHO. • Recommend consuming between 20% to 35% of total calories from Fat. • Recommend consuming between 10% to 35% of total calories from Protein. • Recommended meal composition includes 60% CHO, 25% protein, 15% Fat (Institute of Medicine).

9. Exercise and Food Intake • Mean energy intakes peak between ages 16 and 29 years then declines thereafter. • For individuals who exercise regularly food intake balances daily energy expenditure. • Lack of precision in regulating food intake at low end of energy expenditure leads to creeping obesity. Rough Estimate Minimum Calories Needed: Current wt (lb) X 23 = total calories for males Current wt (lb) x 20 = total calories for females

10. Exercise and Food Intake • Except for high energy intake at extremes, daily intake does not exceed 4000 kCal for men and 3000 kCal for women. • Some sport activities require extreme energy output (some-times > 1000 cal/hr).

11. Exercise and Food Intake • Phelps told ESPN he eats roughly 8,000-10,000 cal/d, including lots of pizza & pasta. • Breakfast of champions • 3 fried egg sandwiches • 2 cups coffee • 5-egg omelet • 1 bowl grits • 3 slices French toast • 3 chocolate chip pancakes Beijing 4 x 100 freestyle relay, 8-11-08

12. Exercise and Food Intake • To support 6’4”, approximately 190#, training regimen requires ~1,000 cal/hr while training or racing. • Probably eats closer to 6,000 cal/day.

13. Precompetition Meal Preworkout Meal Goal: Maximize muscle & liver glycogen stores and provide glucose for intestinal absorption during exercise. • Be consumed within 3-4 hours before exercising sufficient time to digest & absorb. • Reasons precompetition meal high in CHO: • Foods high in lipid & protein digest slowly • Protein catabolism facilitates dehydration • Contain 150 – 300 g CHO in solid or liquid • Benefits of precomp liquid meal: contribute to fluid needs, absorb rapidly leaving no residue

14. 3 hours before Pasta Stir fry Sandwiches Fajitas Eggs & toast Chicken, potato, veggies Veggie burger 2-3 hours before Bagels Crackers Pretzels Smoothies Cereal and milk Waffles/pancakes Pasta salad Pre-Workout Meals

15. Carbohydrate Needs • Optimal fuel for EXERCISE • Intense training depletes carbohydrate stores (glycogen) resulting in poor performance and fatigue. • Consume carbohydrate with every meal. • In general, carbohydrates (CHO) should always provide at least 55% of total daily calorie (TDC) intake. Ideally 60-70% of TDC. • Needs increase with increased training.

16. Carbohydrate Needs • 3 grams/lb body weight for 1 hour training • 4.5 grams/lb body weight for 2 hours training. • 5 grams/lb body weight for 3 hours training. • 6 grams/lb body weight for 4+ hours training. How many calories per gram of CHO? Sources: Bread, Tortillas, Rice, Vegetables, Bagels, Pasta, Potatoes, Fruit, Sports Drinks, English Muffins, Cereals, Fruit Juices, Soda Pop, Muffins, Crackers, Pita, Pretzels, Popcorn

17. Carbohydrate Needs • Before exercise • consuming rapidly absorbed, high glycemic CHO w/i 1 hr before exercising accelerates glycogen depletion by insulin overshoot rebound hypoglycemia • consuming low glycemic CHO immediately (< 30 min) allows for relatively slow absorption rate into blood • During exercise: 30-60 grams per hour, 5-10 oz of 5-8% CHO electrolyte drink every 15-20 min or 2 gels per hour • After exercise • To speed up glycogen replenishment consume 50-75 g moderate to high glycemic index w/i 15 minutes • Under optimal CHO intake, takes 20 hrs to replenish glycogen stores at rate of 5% per hour.

18. Fluid Intake (Chapter 2) • Fluid needs = body weight X .67 = ounces you require daily NOT including exercise • What should you drink: • Night before: 16 oz. of water before bed • Morning of practice: 16 oz. of water ASA get up • If practice later in day: 16 oz. of water 2 hrs. b4 practice • Pre-exercise: 6-8 oz. water or sports drink 15 min before practice, try avoid carbonated beverages or caffeine, NO fruit juices before exercise – can cause loose bowels & gas • During exercise: 4-8 oz. every 15 minutes water & sports drink alternate between two • Post exercise: 15 oz. for every pound lost w/i 2 hrs. exercise

19. Fluid Intake Recommendations • Monitor dehydration rate from BW changes. Each pound (.45 kg) ~ 450 mL • Rate of stomach emptying affects intestinal absorption. Fluid volume within stomach exerts greatest effect on rate of gastric emptying. • To maintain a relatively large fluid volume in stomach & speed gastric emptying, consume 400-600 ml (13.5-20.3 oz) 10 – 20 minutes before, • With subsequent regular ingestion of [250 ml 8.45 oz] every ? throughout exercise.

20. Fluid Intake • To optimize water & CHO absorption use a 6% carbohydrate-electrolyte solution. • Adding sodium to rehydration beverage maintains plasma osmolarity, reduces urine output, motivates. • Theoretically, water absorption across intestinal mucosa may be enhanced by concurrent absorption of glucose & Na. • Glucose stimulates sodium absorption, sodium is necessary for glucose absorption, and co-transport stimulates water’s passive uptake by osmotic action. Best ways to replace K & Na post-exercise: • Orange juice & salted pretzels, Baked potato with ketchup or salt, • Nectarine and some Chex mix, Mix of dried apricots and salted nuts

21. Carbohydrate Needs in Intense Exercise • Successive days of intense training gradually deplete glycogen reserves even with typical CHO intakes. • When dietary CHO increased to 70% of caloric intake, no further glycogen depletion.

22. Carbohydrate Needs Glycogen Loading: procedure increases muscle glycogen levels more than normal (1.7 g/100 g) • Amount of glycogen that can be packed in: • 5 g glycogen/ 100 g muscle • What is major benefit of carbohydrate loading? • Endurance capacity • Unless athlete begins competing completely depleted, exercise < 60 min requires normal carbohydrate intake • Each gram glycogen stores 2.7 grams H2O, makes “heavy” fuel.

23. Carbohydrate Needs • Classic Carbohydrate Loading • Stage 1: depletion • Day 1: perform exhaustive exercise to deplete • Days 2, 3, 4: Maintain low CHO food intake • Stage 2: loading • Days 5, 6, 7: maintain high CHO food intake • Stage 3: competition • Modified Loading • Days 1-3: exercise @ 75% VO2 max, 1.5 hrs, 50% CHO • Days 4-6: taper exercise duration, 70% CHO

24. Fat Needs • Too much can cause cramps • Not enough can cause fatigue more quickly • Try to limit high fat foods before and during exercise. • Foods to avoid before & during exercise: chips, ice cream, nuts, nut butters, french fries, doughnuts, fried meats, pizza, chocolate, bologna, salami, pepperoni, burgers • In general, limit TDC intake < 30% fat.

25. Protein Needs • Body can’t use more than 1 gram of protein per pound of body weight! • Not immediately available as an energy source for exercise. • Important for recovery and to boost immune system. • Sources: chicken, turkey, soy burgers, fish, eggs, dried beans, beef, cheese, nuts and nut butters, pork, milk, veal, shellfish • In general, 15-20% TDC intake.