Nutrition for Athletes

Water is the most important nutrient for the athlete
Carbohydrates (bulk of calorie intake for sports)
1. Athlete requires 5-10 grams/kg/day
2. Carbohydrates comprise 65-70% of daily calories
Protein
1. General population Protein requirements
  1. Recommended Daily Allowance = 0.8 g/kg/day
2. Protein requirements for athletes
  1. Athletes require 1.8 grams/kg/day
  2. Athletes Protein intake and output
    1. Comprise 15-20% of total dietary calories
    2. Comprise 5-10% of caloric use during Exercise
  3. Excess Protein does not benefit strength or mass
    1. Residual Protein is lost in the urine
Fats comprise 15-20% of an athletes total calories
1. Not utilized until 20 minutes into Exercise
2. Important for prolonged, low intensity Exercise
3. Limit to unsaturated fat (e.g. vegetable or fish oil)

Maximizes intensity and endurance of Exercise
Maintains Muscle glycogen
Added to fluids for faster absorption
Increase Carbohydrate before Exercise (70% of calories)
1. Start increase the day before
2. Consume up to 2-5 hours before competition
3. Liquid Carbohydrate may be taken 60 minutes before
4. Benefit appears to be regardless of Glycemic Index
Avoid Reactive Hypoglycemia from Insulin surge
1. Avoid Carbohydrates within 60 minutes of Exercise
2. Highest Hypoglycemia risk with high Glycemic Foods
  1. Glucose
  2. Sucrose
  3. Maltodextrin
3. Low Glycemic Foods may not result in Insulin surge
During endurance competitive event
1. Consider Carbohydrate intake during endurance event
2. Several studies show performance benefit
3. Solid Carbohydrates may be equivalent to liquid
4. Maintaining adequate hydration is paramount
After competitive event
1. Drink or eat 50 gram high glycemic Carbohydrate ASAP
2. Repeat high Glycemic Foods every 2 hours
3. Take in over 100 grams Carbohydrate in 4 hours
4. Take in over 600 grams Carbohydrate in 24 hours
5. Start simple, liquid high Glycemic Food and advance

Multivitamin used by up to 80% of athletes
Supplementation results in no performance improvement
Supplementation may be beneficial in specific cases
1. Iron and Calcium may be deficient in women
2. Vitamin B12 may be deficient in strict Vegetarians

Precautions
1. Overhydration (and associated Hyponatremia) is as problematic as underhydration
Stay hydrated
1. Drink 1 quart non-caffeinated fluid per 1000 calories
Preload fluid 10-30 minutes before competition
1. Drink 250 to 1000 ml of liquid
During Exercise
1. Drink 4-8 ounces (150 to 250 ml) every 15 minutes
  1. Current recommendations are to drink to thirst to avoid overhydration and Hyponatremia
  2. Some recommend limit of 800 ml per hour
2. Drink cool water
  1. Temperature for maximal water absorption: 40 F
3. Add 5-8% Carbohydrates if Exercise >45 minutes
  1. Carbohydrate intake totals 30 to 75 grams per hour
  2. Sports Drinks also contain Electrolytes and can reduce Hyponatremia risk
    1. However, most sport drinks are hypotonic and carry Hyponatremia risk with overhydration
Post event
1. Replace each pound of weight loss with 480 ml (16 oz)
2. Replace half fluid losses in first 4 hours
3. Replace half fluid losses in next 8 hours