sportsnutrition

1. Nutrition and Nutritional
Supplements in Sports

2. Performance Influencing Factors
Genetics
Training and Conditioning
Nutrition

3. Determinants of the Athlete’s
Energy Requirements
 During intense exercise
 Carbohydrate stored in muscles and liver
(glycogen) is predominant fuel source
 During prolonged exercise
 Fat stores are predominant fuel source
 Fitness level of the athlete
 Well trained endurance athletes burn fat more
efficiently, sparing limited glycogen stores

4. Formula for Estimating the
Body’s Calorie Requirements
 Sedentary person
 Weight (kg) x 25
 Moderately active person
 Weight (kg) x 30
 Active person (endurance athlete)
 Weight (kg) x 40
 Underweight person
 Weight (kg) x 45
 kg = lbs / 2.2

5. Carbohydrates
 Non-essential nutrient (human body can make sugar)
 Simple (sugars) and Complex (starches)
 Major fuel source for exercising muscle
 Athletes should ingest 6 to10 gm/kg/day
 60 to 70% of total calories should come from carbohydrates
 Complex carbohydrates (starches) are preferable
 During exercise
 Athletes should consume 25 to 30 gm of carbohydrate for
every 30 minutes of exercise
 Athletes should drink 6 to 8 ounces of water or sports drink for
every 10 to 15 minutes of exercise

6. Carbohydrates
 After exercise
 Athletes should consume 1.0 to 1.5 gm/kg
immediately post exercise and again one
hour later
 To replace muscle glycogen stores
 To prevent gradual depletion of muscle
glycogen stores over time caused by repetitive
daily bouts of heavy exercise
 To decrease muscle breakdown

7. Why Complex Carbohydrates?
 Compared to ingesting simple carbohydrates,
ingesting complex carbohydrates:
 Increases muscle glycogen stores better
 Improves performance and delays fatigue
 Promotes faster stomach emptying
 Causes less stomach upset and indigestion
 Leads to lower blood sugar and insulin levels
 Provides other beneficial nutrients
 Fiber, vitamins and minerals

8. Pre-exercise Meal
 Importance
 Less hunger before and during exercise
 Maintains optimum glycogen stores
 Recommendations
 Emphasize complex carbohydrates (starches)
 1 to 4 gm/kg about 1 to 4 hours prior to event
 Consume less closer to event
 Avoid high fat and high protein foods
 Slower gastric emptying can cause stomach upset
 Avoid high fiber or gas forming foods
 Can lead to crampy abdominal pain

9. Carbohydrate Loading
 Increases the body’s pre-exercise
glycogen stores by 50 to 100%
Benefits endurance athletes who
compete for longer than 90 minutes
 Can increase endurance up to 20%
 Can increase performance by 2 to 3%

10. Comparison of Diets
Low CHO diet (40%
kcal from CHO)
 Double
cheeseburger
 Medium fries
 Chocolate
milkshake
 High CHO diet
(70% kcal from
CHO)
 12 inch sub
sandwich (lots of
vegetables & no
mayo)
 500 ml apple juice
 250 ml chocolate
milk
 banana

11. Effects of Diet on Muscle Glycogen
Content
140
120
100
80
60
40
20
Time
Muscle Glycogen
(mM/kg wet wt)
High CHO
Low CHO

12. Carbohydrate Snacks
 Foods supplying 50 grams CHO
 500 ml juice
 3 medium pieces of fruit
 1 honey sandwich
 2 breakfast bars
 1 sports bar (check label)
 1.3 bagels
 1/2 cup dried fruit
 1 cup white rice
 1 baked potato
*average 70 kg endurance athlete should consume 560
grams CHO per day

13. Carbohydrate Loading:
One Example of How
Days prior to event Exercise duration Carbohydrate intake
6 90 minutes 5 gm/kg/day
5 40 minutes 5 gm/kg/day
4 40 minutes 5 gm/kg/day
3 20 minutes 10 gm/kg/day
2 20 minutes 10 gm/kg/day
1 rest 10 gm/kg/day

14. Protein
 Athletes require more protein than non-athletes
 12 to 18% of total calories should come from protein
 Protein intake should be tailored to type of training
 1.2 to 1.4 gm/kg/day recommended for endurance athletes
 1.7 to 1.8 gm/kg/day recommended for strength athletes
 Average American diet provides 1.4 gm/kg/day
 Adequate calorie intake is just as important as
adequate protein intake for building muscles
 Too much protein intake can be bad
 Excess protein calories are stored as fat
 Excess protein intake can lead to dehydration and may
contribute to kidney problems

15. Fat
 Major source of energy
 25 to 30% of total calories should come from fat
 Less than 10% of total calories should come from
saturated fats
 Cholesterol intake should be less than 300 mg/day
 Average American diet provides 37% of total
calories from fat

16. Nutritional Supplements
 1994 Dietary Supplement Health and
Education Act
 Definition of a supplement
 Any product that contains vitamins, minerals,
amino acids, herbs, botanicals or a
concentrate, metabolite, constituent, extract or
combination of any of these ingredients
 Removed dietary supplements from FDA
regulation on the front end
 FDA must prove a supplement is dangerous
before its sale can be prohibited

17. Nutritional Supplements
1994 Dietary Supplement Health and
Education Act
 Manufacturers do not have to provide
scientific proof of claims
 Manufacturers cannot state product is
meant to diagnose, treat, prevent or cure a
disease but can make indirect suggestions
 Created a multi-billion dollar industry that
continues to grow rapidly

18. Vitamins and Minerals
 Essential nutrients
 Human body needs these to produce energy
 No evidence in U.S. studies that taking vitamin and
mineral supplements improves athletic performance
 Being deficient in vitamins or minerals is rare in the U.S.
compared to the rest of the world
 A few studies outside U.S. showed an effect
 Did population studied have some baseline deficiency
treated with these supplements?
 Vegetarian athletes are at risk for being deficient in
vitamins B12, D, riboflavin, iron, zinc and calcium
 Athletes who are strict vegetarians should take a
multivitamin to prevent deficiencies and a calcium
supplement (1000 mg/day) to help prevent bone loss

19. Conclusions
 Nutrition plays an important role in an endurance
athlete’s ability to perform
 Proper nutrition in combination with sound and
proven training techniques can help endurance
athletes to maximize their genetic abilities
 Certain nutritional supplements have not
demonstrated any performance benefit in studies

20. Conclusions
 Certain nutritional supplements can have
potentially dangerous side effects
 Further legislation is needed to address the
dangers of some nutritional supplements
 Professionals in the community need to be
resources of good information for athletes,
parents and coaches
 Physicians
 Physician assistants
 Nurse practitioners
 Athletic trainers
 School nurses
 Dieticians