Eating for Exercise
by Timothy M. Brewi, BA, DTR
1. Food Before Exercise
• Most importantly,
be sure you’re well hydrated before exercise. Exercise performance
suffers with as little as 2% loss of body weight due to dehydration.
Drink at least 2 cups of water about 2 hours before exercise.
Drink another 2 cups of water within 20 minutes of exercise.
• Don’t exercise when
the body is depleted of nutrients (like before breakfast).
Note that performing aerobic exercise on an empty stomach
or when you’re hungry does not increase the amount of fat
you burn; rather, it may cause protein to be sacrificed as
fuel.
• For optimum exercise
performance, be sure to consume a healthy, well-balanced diet
all through the day! (For more information on healthy food
choices, go to http://www.tbrewi.com/hivfitness/food.htm)
• Don’t exercise immediately
after eating, because the body shifts fluid away from muscles
and into the gastrointestinal tract during digestion. The
ideal time for fitness activities is about…
• 1/2 hour after a light snack.
• 1 hour after a light meal, heavy
snack, or meal replacement drink.
• 2 hours after a regular meal.
• 3 hours after a Thanksgiving-type
feast.
• Consuming sweets
(such as honey, candy, or soda) immediately before exercise
does not provide a quick burst of energy, but may cause a
rise in insulin followed by a drop in blood sugar resulting
in fatigue.
2. Food During Exercise
• Most importantly,
be sure to drink plenty of water during exercise. Drinking
water during exercise does not cause upset stomach or cramps;
whereas restricting water during exercise may cause severe
dehydration and limit performance. Be aware that exercise
blunts the sense of thirst. “If you wait until you notice
your thirst, you’re already becoming dehydrated.” So whether
you feel thirsty or not, drink 1/2 cup of water every 10-15
minutes. Ideally, exercisers should consume adequate fluids
during activity so that body weight remains relatively unchanged
before and after exercise.
• Note that muscle
cramps are not caused by inadequate salt intake, but by excess
water loss through perspiration. Salt tablets will aggravate
dehydration by drawing fluids into the stomach. Prevent muscle
cramps during exercise by keeping well hydrated.
• For people who exercise
up to an hour in moderate environmental conditions, the most
appropriate fluid to drink is cool water. The typical American
diet provides ample electrolytes (sodium, potassium, chloride,
and magnesium) to replace what is lost by sweat. However,
persons who exercise strenuously for more than an hour or
exercise in extreme environmental conditions (neither of which
is recommended!) may require a sports beverage containing
carbohydrates and electrolytes.
• Don’t consume food
during exercise, because the body shifts fluid away from muscles
and into the gastrointestinal tract for digestion.
3. Food After Exercise
• Most importantly,
drink more water! If you don’t believe you lose much water
during exercise, weigh yourself immediately before and after
exercise. The difference is water loss. Ideally, exercisers
should consume adequate fluids during activity so that body
weight remains relatively unchanged before and after exercise.
• Sorry… If you lost
weight during exercise, the loss is not due to burning fat
but to losing water. Consume 2 cups of water for every pound
of body weight lost during exercise.
• Note that muscle
cramps are not caused by inadequate salt intake but by excess
water loss through perspiration. Salt tablets will aggravate
dehydration by drawing fluids into the stomach. Prevent muscle
cramps after exercise (especially the night after exercise)
by keeping well hydrated.
• Don’t consume a heavy
meal in the first hour after exercise.
• Do enjoy a snack
or light meal about 30 minutes after exercise. The ideal post-exercise
snack is light and nutritious, containing mainly carbohydrates
and protein in a ratio of about 2:1. Examples:
• 1 cup of fruit juice with protein
powder.
• 1 cup of 1% milk, fat-free ice
cream, or nonfat yogurt.
• 1 apple with 1 inch cube of
low-fat cheese.
• 2 slices of whole wheat bread
with 2 thin slices of turkey, optional mustard.
• To achieve the best
results from exercise, be sure to consume a healthy, well-balanced
diet all through the day!
Reprinted with permission
from HIV Fitness guidelines. (at http://www.tbrewi.com/hivfitness/foodbda.htm).
References are available online.
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