Clinic nutrition2014

Nutrition and Nutritional

Supplements in Sports

Performance Influencing Factors

Genetics

Training and Conditioning

Nutrition

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

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

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

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

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

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

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%

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

20

40

60

80

100

120

140

Time

Mu

scle

Gly

co

gen

(m

M/k

g w

et

wt)

High CHO

Low CHO

Effects of Diet on Muscle Glycogen

Content

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

Carbohydrate Loading:

One Example of How

Days prior to event Exercise duration Carbohydrate intake

6 90 minutes 5 gm/kg/day





1 rest 10 gm/kg/day

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

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

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

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

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

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

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