Presentation on theme: "Nutrition for Exercise & Sport"— Presentation transcript:
1 Nutrition for Exercise & Sport Exercise PhysiologyMcArdle, Katch, Katch: Chapter 3
2 Overview Nutrient Consumption: Fit & Non-fit Dietary Reference Intakes Calorie and Macronutrient NeedsPre workout (competition) MealWaterCarbohydrateFatProteinAdding Mass: Gaining Weight
3 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 intakesDiets more closely approach recommendationsSound human nutrition represents sound nutrition for athletes.
4 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.
5 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.
6 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.
7 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).
8 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.
9 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.
10 Exercise and Food Intake Phelps told ESPN he eats roughly 8,000-10,000 cal/d, including lots of pizza & pasta.Breakfast of champions3 fried egg sandwiches2 cups coffee5-egg omelet1 bowl grits3 slices French toast3 chocolate chip pancakesBeijing 4 x 100 freestyle relay,
11 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.
12 Exercise and Food Intake Minimum: current wt (lb) X 23 = total calories for malesCurrent wt (lb) x 20 = total calories for femalesRelatively 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.
13 Precompetition MealPre-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 slowlyLow CHO meal can hinder performanceContain 150 – 300 g CHO in solid or liquidBenefits of precomp liquid meal: contribute to fluid needs, absorb rapidly leaving no residue
14 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.
15 Carbohydrate Needs*More intense or prolonged training requires more carbohydrate3 grams/lb body weight for 1 hour training4.5 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
16 Carbohydrate Needs Before exercise pre-exercise fructose absorbs more slowly, but GI distressconsuming 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: grams per hour, 5-10 oz of 5-8% CHO electrolyte drink every min or 2 gels per hour; drink contributes to temperature regulationAfter exerciseTo speed up glycogen replenishment, consume 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.
17 Fluid Intake (Chapter 2)* Fluid needs = body weight X .67 = ounces you require daily NOT including exerciseWhat should you drink:Night before: 16 oz. of water before bedMorning of practice: 16 oz. of water ASA get upIf practice later in day: 16 oz. of water 2 hrs. b4 practicePre-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 & gasDuring exercise: 4-8 oz. every 15 minutes water & sports drink alternate between twoPost exercise: 24 oz. for every pound lost w/i 2 hrs. exercise
18 Fluid, Glucose, and Electrolyte Intake RecommendationsFluid volume within stomach exerts greatest effect on rate of gastric emptying.To maintain a relatively large fluid volume in stomach & speed gastric emptying, consume ml ( 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.
19 Sodium Potential Benefit* Sodium benefits ultraendurance athleteat risk for hyponatremia.Adding sodium to rehydration beveragemaintains plasma osmolarity, reducesurine output, motivates drinking.Theoretically, water absorption acrossintestinal 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 saltNectarine and some Chex mix, Mix of dried apricots and salted nuts
20 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.
21 Carbohydrate LoadingGlycogen 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 muscleWhat is major benefit of carbohydrate loading?Endurance capacityUnless athlete begins competing completely depleted, exercise < 60 min requires normal carbohydrate intakeWhat is major drawback of glycogen loading?Each gram glycogen stores 2.7 grams H2O, makes “heavy” fuel.
23 Fat Needs* Too much can cause cramps Not enough can cause fatigue more quicklyTry 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, burgersIn general, limit TDC intake < 30% fat.
24 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, shellfishIn general, 15-20% TDC intake.
29 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.
30 Goals* Adding Mass Goals for weight & strength gain = 1 lb/wk 10-14 additional grams protein/day 1 lb muscle mass/weekGoals to add additional calories/dayIncrease number of meals, not just size mealsDon’t rely on weight gainers or high protein powders. Fill you up before get in all calories
31 Illustration References McArdle, William D., Frank I. Katch, and Victor L. Katch Essentials of Exercise Physiology 2nd ed. Image Collection. Lippincott Williams & Wilkins.Plowman, Sharon A. and Denise L. Smith Digital Image Archive for Exercise Physiology. Allyn & Bacon.Carmichael, Chris The Lance Armstrong Diet, Men’s Journal, Aug. p. 38.