Optimal Nutrition and Sport

Dietary Guidelines for
American Adults and Athletes

l Eat a variety of foods

l Balance food intake with physical activity-maintain or improve body weight

l Choose a diet with plenty of unrefined grain products, vegetables, and fruits

l Choose a diet low in total fat, saturated fatty acids, and cholesterol

l Choose a diet moderate in sugars

l Choose a diet moderate in salt and sodium

l If you drink alcoholic beverages, do so in moderation

Energy Balance in Athletes

l Generally, athletes naturally consume significant calories to maintain their body weight

l The greater the extremes of competition, the greater need for food intake.

Athletes Who Require Supplementation

l High energy demands of certain sports require additional nutrients

– Gymnastics

– Ballet Dancers

– Ice Dancers

– Weight-class athletes

l Boxing

l Wrestling

l Judo

l Athletes in high energy sports are often deficient in CHO’s and require 1.2 to 1.8 grams/kg of body mass

Specific Recommendations for Athletes

l 23 kcal per pound per day (or 50 kcal/kg/day)

l 60-70% Carbohydrate

l < 25% Fat

l 15-20% Protein

The Precompetition Meal

l Should consider the following factors:

– Food preference

– “Psychologic set” of competition

– Digestibility of foods

“Ideal” Precompetition Meal

l Meal should:

– Contain 150 to 300 grams of CHO (3-5 g per kg of body mass) in either solid or liquid form

– Be consumed within 3 to 4 hours before exercising

l CHO digest faster than fats and protein

l Increased emotional stress may slow digestion since blood flow will be less to digestive tract

l CHO replenish lost glycogen from overnight fast better than fat and protein

l High protein meals elevate resting metabolism and thus use more of body’s energy before exercising

l High protein meals contribute to dehydration during exercise

– Involve use of low “glycemic index” foods

Liquid meals for Precompetition?

l Provide needed energy and nutrients

l Provide high CHO content for replenishment of used glycogen in the body

l Contain some lipid and protein to contribute to satiety

l Supply fluid to body

l Digest rapidly

CHO intake before, during and after exercise

l Before Exercise:

– Consume 400-600 ml of fluid immediately before exercise to optimize passage of nutrients in digestive tract

– Avoid simple sugars within 30 min of exercise; should be ingested at least 60 minutes prior to exercise

– For long duration exercise, may consider CHO loading

CHO Loading (Glycogen Supercompensation)

l Classic Approach

– 6 days prior to competition, do high intensity aerobic exercise for 90 min.

– Maintain low-CHO diet (60-100 g/day) for 3 days while training at moderate intensity

– Switch to high-CHO diet (400-700 g/day) at least 3 days prior to competition and maintain up to race

l Modern Approach

– High-CHO diet the day before the race

During Exercise

l For high-intensity, long duration exercise:

– Fluid ingestion should be ~250 ml at 15 minute intervals

– Consume 60 grams of liquid or solid CHO each hour of exercise

l 5-8% CHO drinks are recommended

– Examples: Gatorade, 10 K, Everlast

l Avoid drinks above 8% CHO

– Examples: Coke, orange juice (these are ~10%)

l For low-intensity, long duration exercise:

– No significant need to consume large amounts of CHO since fat is a primary fuel source

After Exercise

l Within initial 24 hours post-exercise:

– Simple or complex CHO may be ingested (50-75 grams of CHO every 2 hours until total of 500 grams achieved)

l At 24-48 hours post-exercise:

– Complex CHO are recommended

l Glycogen replenishes at a rate of 5% per hour under optimal conditions, hence it will take at least 20 hours to replace lost glycogen from exercise