Nutrition for Exercise & Sport Exercise Physiology McArdle, Katch, Katch: Chapter 3

Overview Nutrient Consumption: Fit & Non-fit Dietary Reference Intakes Calorie and Macronutrient Needs Pre workout (competition) Meal Water Carbohydrate Fat Protein Adding Mass: Gaining Weight

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

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.

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.

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.

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).

Exercise and Food Intake Mean energy intakes peak between ages 16 and 29 years & 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.

Exercise and Food Intake Most obvious distinction in nutrient needs between active and inactive is more total calories. Except for high energy intake at extremes, daily intake does not exceed 4000 kCal for men and 3000 kCal for women.

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

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.

Exercise and Food Intake Minimum: current wt (lb) X 23 = total calories for males Current wt (lb) x 20 = total calories for females Relatively high caloric intakes of physically active men & women usually increase protein, vitamin, and mineral intake above normal. Percentage of calories from energy nutrients should remain in normal ranges.

Precompetition Meal Pre-workout meal goal: maximize muscle & liver glycogen stores providing glucose for intestinal absorption during exercise & enhance hydration. 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 Low CHO meal can hinder performance Contain 150 – 300 g CHO in solid or liquid Benefits of precomp liquid meal: contribute to fluid needs, absorb rapidly leaving no residue

Carbohydrate Needs* Carbohydrate is the optimal fuel for exercise Prolonged and intermittent, intense training depletes carbohydrate (glycogen) stores 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.

Carbohydrate Needs* More intense or prolonged training requires more carbohydrate 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, Bagels, English Muffins, Cereals, Rice, Pasta, Vegetables, Potatoes, *Fruit, Fruit Juices, Sports Drinks, Soda Pop, Crackers, Pita, Pretzels, Popcorn

Carbohydrate Needs Before exercise pre-exercise fructose absorbs more slowly, but GI distress consuming rapidly absorbed, high glycemic CHO w/i 1 hr before exercising accelerates glycogen depletion by causing insulin overshoot & rebound hypoglycemia. consuming low glycemic CHO immediately (< 30 min) allows for relatively slow absorption. 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; drink contributes to temperature regulation 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.

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: 24 oz. for every pound lost w/i 2 hrs. exercise

Fluid, Glucose, and Electrolyte Intake Recommendations 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) [immediately] 2 hrs before and __?_ 15 min before exercise; With subsequent regular ingestion of [250 ml 8.45 oz] ? every throughout exercise. To optimize water & CHO absorption use a 6% carbohydrate-electrolyte solution (not too dilute or too concentrated). Adding sodium to rehydration beverage maintains plasma osmolarity, reduces urine output, motivates.

Sodium Potential Benefit* Sodium benefits ultraendurance athlete at risk for hyponatremia. Adding sodium to rehydration beverage maintains plasma osmolarity, reduces urine output, motivates drinking. Theoretically, water absorption across intestinal mucosa may be enhance by concurrent absorption of glucose and 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

Carbohydrate Needs in Intense Exercise* Successive days of intense training gradually deplete glycogen reserves even with typical CHO intakes: staleness. High CHO diet (80% of caloric intake) for 3 days increased muscle _______ and endurance time.

Carbohydrate Loading Glycogen Loading: procedure increases muscle glycogen levels more than normal (1.7 g/100 g). Normal amount of glycogen packed in muscle: 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 What is major drawback of glycogen loading? Each gram glycogen stores 2.7 grams H2O, makes “heavy” fuel.

Carbohydrate Loading Classic Carbohydrate Loading Modified 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

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.

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.

Periodization of Calorie Needs*

Baseball Guidelines*

Basketball Guidelines*

Football Guidelines*

Nutrient Timing Resistance Training Energy Phase: immediately pre- & during exercise period consume high glycemic CHO & rapidly digested PRO supplement. Anabolic Phase: consume high glycemic CHO/PRO in liquid form during 45-minute post-exercise. Growth Phase: from end of anabolic to beginning next workout, high glycemic CHO and high PRO intake.

Goals* Adding Mass Goals for weight & strength gain = 1 lb/wk 10-14 additional grams protein/day  1 lb muscle mass/week Goals to add 500-100 additional calories/day Increase number of meals, not just size meals Don’t rely on weight gainers or high protein powders. Fill you up before get in all calories

Illustration References McArdle, William D., Frank I. Katch, and Victor L. Katch. 2000. Essentials of Exercise Physiology 2nd ed. Image Collection. Lippincott Williams & Wilkins. Plowman, Sharon A. and Denise L. Smith. 1998. Digital Image Archive for Exercise Physiology. Allyn & Bacon. Carmichael, Chris. 2005. The Lance Armstrong Diet, Men’s Journal, Aug. p. 38.