Section 5 Section 5

Eating For Training and Competition

The Optimal Diet (in general and for physical activity)The Optimal Diet (in general and for physical activity)

Supplies required nutrients in adequate amounts for tissue maintenance, repair, and growth without excess energy intake

Proper nutrition helps:

• Improve athletic performance

• Optimize programs of physical conditioning

• Improve recovery from fatigue

• Avoid injury

Energy Balance Equation Energy Balance Equation

Body mass remains constant when caloric intake equals caloric expenditure.

3500 kCal approximately equals 1 lb of stored body fat.

Consume 3500 extra kCal, gain 1 pound

Burn 3500 kCal, lose 1 pound

Principles of Good Eating Principles of Good Eating Variety

• Choosing foods from a variety of sources creates a diet that contains sufficient amounts of all required nutrients.

Balance

• Balance in one’s diet indicates the intake of nutrients from the major food groups.

Moderation

• Eating moderately requires appropriate planning to maintain a balanced nutrient intake throughout the day.

MyPyramidMyPyramid

www.mypyramid.gov

Can be personalized based on age, sex, and level of daily exercise

Includes a figure walking up the side of the pyramid to emphasize at least 30 minutes of moderate to vigorous daily physical activity

Based on the 2005 Dietary Guidelines for Americans

Dietary Guidelines for AmericansDietary Guidelines for Americans

Control caloric intake to manage body weight.

Consume a variety of foods.

• Within the basic food groups

Increase daily intake of fruits, vegetables, whole grains, beans, and nonfat or low-fat milk and milk products.

Choose fats wisely for good health.

• Limit saturated fats and trans fats.

• Choose fish or plant-based fats.

Dietary Guidelines for Americans (cont.)Dietary Guidelines for Americans (cont.)

Choose carbohydrates wisely for good health.

Choose and prepare foods with little salt.

If you drink alcoholic beverages, do so in moderation.

Be physically active every day.

Keep food safe to eat.

Serving Size Versus PortionsServing Size Versus Portions

The USDA defines a standard serving of pasta as one-half cup.

The FDA, which regulates food labels, claims a standard serving is 1 cup.

Typical restaurant pasta portion averages about 3 cups.

• Equal to 6 servings according to MyPyramid

Mediterranean and Vegetarian Diet Pyramids Mediterranean and Vegetarian Diet Pyramids

Mediterranean

• Emphasizes fruits, nuts, vegetables, legumes, all manner of unrefined grains, and protein derived from fish, beans, and chicken

• High monounsaturated fatty acid content

Vegetarian

• Consists of foods from the plant kingdom

Protein Intake among the Physically ActiveProtein Intake among the Physically Active

RDA = 0.8 g/kg of body mass Eating a high-carbohydrate diet with adequate energy intake conserves muscle protein in

individuals who engage in protracted intense training.

-Sedentary but healthy individuals: 0.8 g of protein per kg of body weight

ie: 125 lbs = 70 kg – needs 56 g of protein

liberal allowance

-Physically active individuals: 1.0 g/kg BW

-Typical athletes: 1.0-1.2 g/kg

-Endurance athletes and strength athletes: 1.2-1.5 g/kg

”Heartily sufficient reserve”

This level is within the range of typical intakes for athletes

*obviates the need for supplementary proteins

Protein Supplements Protein Supplements

Some athletes supplement with simple amino acids.

Advocates believe the body absorbs the simple amino acid molecule more readily.

The healthy intestine absorbs amino acids rapidly when they exist in more complex di- and tripeptide molecules, not just in simple amino acid form.

*may lessen the immunological (and cortisol) mediated breakdown of tissue immediately after exercise

Vegetarian Athletes:Increasing numbers of athletes consume diets consisting predominately of

nutrient from plant sources, and some dairy and meat products.-Carl Lewis: 9 Olympic gold medals in track and field-Dave Scott: 4 time World Iron Man Triathlete-Sean Yates: professional cyclist-Murray Rose: 4 Olympic god medals in swimming-Billie Jean King: professional tennis player-Martina Navratilova: professional tennis player-Bill Manetti: powerlifting champion-Bill Pearl: 4 time “Mr. Universe” bodybuilder

Lipid Intake among the Physically ActiveLipid Intake among the Physically Active

To promote good health, lipid intake should probably not exceed 30% of the diet’s energy content.

• Of this, at least 70% should come from unsaturated fatty acids.

Significant reductions in dietary lipid compromise exercise performance.

Lipids are necessary to obtain essential fatty acids and fat-soluble vitamins.

Carbohydrate Intake among the Physically ActiveCarbohydrate Intake among the Physically Active

Yeah, this is the most important macronutrient

A low-carbohydrate diet rapidly compromises energy reserves for vigorous physical activity or regular training.

Physically active individuals should consume at least 55-65% of calories as carbohydrates, predominantly starches from fiber-rich, unprocessed grains, fruits, and vegetables.

Endurance training = 10 g of carbohydrate per kg of body mass per day

Vitamin-Mineral DeficienciesVitamin-Mineral Deficiencies

Most often occur in:

• Vegetarians or groups with low energy intake

• Those who eliminate one or more food groups from their diet

• Individuals who consume large amounts of processed foods and simple sugars with low micronutrient density

Vitamin SupplementsVitamin Supplements

50 years of research fail to support the use of vitamin supplements to improve aerobic and anaerobic exercise performance.

Maybe C? Daily supplements of 500-1500 mg of vitamin C per day may confer some benefit to individuals engaged in strenuous exercise who experience frequent viral infections.

RDA is 60 mg

120 mg is the most you can absorb in 24 hours

Be careful of consuming MegavitaminsBe careful of consuming Megavitamins

Contain doses at least 10 and up to 1000 times the RDA

Excess vitamin C = kidney stones

Excess vitamin B6 = liver disease and nerve damage

Excess riboflavin (B2) = impaired vision

Excess niacin = vasodilation and inhibition of fatty acid mobilization during exercise

Folate = trigger an allergic response

Excess vitamin E = headache, fatigue, blurred vision, gastrointestinal disturbances, muscular weakness, and low blood sugar

Excess vitamin A = toxic to the nervous system

Excess vitamin D = damages kidneys

AntioxidantsAntioxidants

Aerobic exercise metabolism increases the production of free radicals.

Dietary Antioxidants help prevent:

• ß-Carotene

• Vitamin C

• Vitamin E

• Selenium, copper, manganese, and zinc

• Coenzyme Q10

• BUT! Dietary antioxidants suppress endogenous antioxidant production

• Glutathione peroxidase

• Superoxide dismutase

• Alpha lipoic acid

• Catalase

• Uric Acid (blood)

Antioxidants (the rest of the story)Antioxidants (the rest of the story) Antioxidant Supplements Blunt Exercise-Induced

Improvement of Insulin Sensitivity    Comment: Surprisingly, use of antioxidant supplements blunts the beneficial effects of regular exercise… Overall, little evidence of benefit from regular use of vitamin C or E supplements exists, and this study offers one reason to discourage their use and to encourage diets that are rich in fruits and vegetables. - Anthony L. Komaroff, MD

Moderation….

MineralsMinerals

Excessive sweating during exercise causes loss of body water and related minerals.

Mineral loss should be replaced following exercise through well-balanced meals.

Single-mineral supplementation is ill advised unless prescribed because of potential adverse consequences.

Exercise and Food Intake Exercise and Food Intake

Energy intake needs to be balanced with energy expenditure.

Individuals who engage regularly in moderate-to-intense physical activity eventually increase daily energy intake to match their higher level of energy expenditure.

Many athletes, particularly females, do not meet energy intake recommendations.

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins

Eating for Competition:Eating for Competition:

• Pre-competition

• During competition

• After competition

*Training sessions too

The Precompetition Meal The Precompetition Meal

Readily digestible foods

Should contribute to energy and fluid requirements

Meals high in carbohydrates and relatively low in lipids and proteins

Three to four hours to digest and absorb the precompetition meal

*Carbs before and during – Protein and carbs after

Ideal Precompetition MealIdeal Precompetition Meal

The ideal precompetition meal:

• Contains 150 to 300 grams of carbohydrates

• Is consumed 3 to 4 hours before the event

• Contains little fat

• Contains little fiber

Liquid MealsLiquid Meals

High carbohydrate content

Supply fluids

Digest rapidly

Can be used for day-long events

Supplement calorie intake in those with difficulty maintaining body weight

Nutrition BarsNutrition Bars

High protein content

Approximately 25 g of carbohydrate

Often include vitamins and minerals

May contain dietary supplements

Should not substitute for normal food intake

Nutrition Powders and DrinksNutrition Powders and Drinks

High protein content

Contain vitamins, minerals, and other dietary supplements

Come in powdered form or premixed

Contain fewer calories per serving than nutrition bars

Carbohydrates before ExerciseCarbohydrates before Exercise

If simple sugars are consumed, they should be consumed at least 60 minutes before exercising.

• This time gives hormones the chance to rebalance.

Fructose absorbs more slowly compared to glucose or sucrose.

• High-fructose beverages can produce significant gastrointestinal distress.

Carbohydrates during ExerciseCarbohydrates during Exercise

Allows for a greater intensity during prolonged activities

Consuming about 60 g of liquid or solid carbohydrates each hour benefits:

• High-intensity, long-duration aerobic exercise

• Repetitive short bouts of near-maximal effort

Spares muscle glycogen

Helps maintain a more optimal blood glucose level

Carbohydrates after ExerciseCarbohydrates after Exercise

High-glycemic carbohydrate-rich foods

Either a single large meal or small frequent meals will replenish glycogen stores.

Should be consumed as soon as possible after the activity

Avoid legumes, fructose, and milk products.

Glycemic IndexGlycemic Index

Indicates how a carbohydrate-containing food affects blood glucose levels

High-glycemic index

Moderate-glycemic index

Low-glycemic index

Affected by food preparation, ripeness, and how foods are combined

Glycogen DepletionGlycogen Depletion

High-intensity aerobic exercise for 1 hour decreases liver glycogen by about 55%.

A 2-hour strenuous workout nearly depletes the glycogen content of the liver and specifically exercised muscles.

Hydration SolutionsHydration Solutions

Carbohydrate-containing solutions consumed during exercise enhance endurance performance by maintaining blood sugar concentration.

Glucose supplied in the blood can:

• Spare existing glycogen in active muscles

• Serve as “reserve” blood glucose for later use should muscle glycogen become depleted

Oral Rehydration SolutionsOral Rehydration Solutions

Provide additional glucose

Minimize the effects of dehydration on:

• Cardiovascular dynamics

• Temperature regulation

• Exercise performance

Adding electrolytes aids in:

• Maintaining thirst mechanism

• Reducing the risk of hyponatremia

Carbohydrate-Electrolyte BeveragesCarbohydrate-Electrolyte Beverages

The ideal hydration solution contains between 5% and 8% carbohydrates.

This permits carbohydrate replenishment without adversely affecting fluid balance and thermoregulation.

Maintains glucose metabolism and preserves glycogen during prolonged exercise

Hydration during ExerciseHydration during Exercise

Adding moderate amounts of sodium to the ingested fluid helps to maintain plasma sodium concentration.

This benefits the ultra-endurance athlete at risk for hyponatremia.

Maintaining plasma osmolality with added sodium in the hydration beverage reduces urine output and sustains the sodium-dependent osmotic drive to drink.

High-Fat DietsHigh-Fat Diets

Conflicting research findings

Detrimental health risks are possible.

Heath risks may not apply to athletes.

Significant restrictions in fat impair exercise endurance.