Nutrition for Exercise Sport Exercise Physiology Mc Ardle

Nutrition for Exercise & Sport Exercise Physiology Mc. Ardle, 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.

Performance Factors • Genetics • Training and Conditioning • Nutrition

Determinants of the Athletes Energy Requirements • During intense exercise – Carbohydrates are stored in muscles and liver are the predominant fuel source • During Prolonged exercise – Fat stores are the predominant fuel source

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 • 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 k. Cal for men and 3000 k. Cal for women.

Exercise and Food Intake • Phelps told ESPN he eats roughly 8, 00010, 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.

Formula for Estamating the Body’s Calorie Requirements • Sedentary person – Weight(kg) x 25 • Moderately active – Weight(kg) x 30 • Active – Weight(kg) x 40 • Underweight person – Weight(kg) x 45

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

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 • During exercise: 30 -60 grams per hour, 510 oz of 5 -8% CHO electrolyte drink every 15 -20 min or 2 gels per hour; drink contributes to temperature regulation

After Exercise 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.

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 H 2 O, makes “heavy” fuel.

Carbohydrate Loading • 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% VO 2 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 • Mc. Ardle, William D. , Frank I. Katch, and Victor L. Katch. 2000. Essentials of Exercise Physiology 2 nd 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.