Eating for Endurance

Posted on January 1, 2008 by

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Eating for Endurance: What, When and Why

By NancyClark, MS, RD

Posted on on February 14, 2005
Copyright: Nancy Clark Feb 2005

Some athletes consider food their reward at the end of the day; they
save up their appetite for a huge feast at dinnertime. Wiser athletes
treat food as fuel; they knowledgeably fuel before, during and after
exercise. They get more out of their workouts and prevent needless
fatigue. If that is your goal, keep reading!

What to eat before you exercise

Contrary to popular belief, pre-exercise food does NOT simply sit in the
stomach and hinder athletic performance. Rather, it enhances stamina and
endurance. The following study confirms this point:
On two occasions, athletes exercised moderately hard until they were
exhausted. In one trial, they ate a 400-calorie breakfast three hours
before exercising. In the second trial, they simply had a dinner the
night before. When they exercised “on empty,” they biked for only 109
minutes, as compared to 136 minutes with the breakfast. That’s almost
half an hour longer! Exercising without fuel left them lagging. (Med Sci
Sports Exerc 31(3):464, 1999)

Even if you eat five minutes before exercise, youll digest the snack
and burn it during exercise, assuming you will be exercising at a pace
you can maintain for more than 30 minutes. This means, you can enjoy a
granola bar and banana on the way to the gym to fuel your workout.
Research suggests this pre-exercise snack can help you perform 10%
harder in the last 10 minutes of a one-hour workout. Go for it!
Your goal is to target 0.5 grams carbohydrate per pound of body weight
within the hour before you exercise. This means, if you weigh 150
pounds, you should target about 300 calories. This is far more than most
athletes consume. Obviously, the amount will depend on your stomach’s
tolerance to this pre-exercise fuel. If you have a finicky stomach,
liquids or semi-solids (Boost, yogurt, applesauce, pudding) might empty
from the stomach quicker than oatmeal, bagel, banana, animal crackers or
graham crackers. The trick is to teach your intestinal track to tolerate
the pre-exercise food so you can avoid undesired pit stops.

Eating During Exercise

If you are exercising longer than an hour, plan to consume carbs and
fluids during exercise to maintain energy and prevent dehydration,
needless fatigue. Depending on your body size, intensity of exercise and
intestinal tolerance, you’ll want to target about 100 to 250 calories of
carbohydrates per hour after the first hour of a 2 or 3 hour event. If
necessary, set your watch to beep every 15-20 minutes as a reminder to
consume 8 ounces of a sports drink, a dried fig or a quarter of an
energy bar + water. If you are doing an Ironman or ultra-distance event,
youll need to consume even more (400-500 calories/hour).

During a moderate to hard endurance workout, carbohydrates in muscle
glycogen and blood glucose supply about half of the energy. As you
deplete muscle glycogen, you increasingly rely on glucose (sugar) in
your blood for energy. By consuming sports drinks, gels, bananas, hard
candies, peppermint patties and other carb-based foods during exercise,
you will fuel your muscles, maintain a normal blood sugar and prevent
the dreaded bonk.

Your brain relies on the glucose in your blood for energy; keeping your
brain fed helps you think clearly, concentrate well, remain focusedand
perform better. Do NOT “hold off” until after your workout to eat.
Rather, fuel during workouts. For example, cyclists should eat while on
the bike. Coaches should give teams a snack break during long (2+ hours)

Your body doesn’t care if you ingest solid or liquid carbohydratesboth
are equally effective forms of fuel. You just have to learn which sports
snacks settle best for your body-gels, gummy bears, dried figs, sugar
wafers, tea with honey, sports drink, defizzed cola? If you get your
energy from solid foods as opposed to sports drinks, be sure to drink
additional fluids. That is, athletes who eat energy bars during exercise
can too easily under-hydrate.

Despite popular belief, sugar (as in sports drinks, jelly beans,
licorice) can be a positive snack during exercise and is unlikely to
cause you to “crash” (experience hypoglycemia). That’s because sugar
taken during exercise results in only small increases in both insulin
and blood glucose. Yet, if you consume too much sugar (>250
calories/hour), the high dose might slow the rate at which fluids leave
your stomach, causing sloshing, discomfort. (If you experience GI
distress, slow down and work at an easier pace.)

Post-exercise Food

If you will not be exercising again for a day or two, you need not worry
about rapid refueling. But if you workout hard twice a day, you should
consume post-exercise carbohydrates as soon as tolerable–ideally 0.5
grams carbohydrate per pound body weight every hour, for 4 to 5 hours
(300 calories per hour, if you weigh 150 pounds). Consuming some protein
along with the carbs stimulates faster glycogen replacement and
optimizes muscular repair and growth.

Some commercial recovery foods tout the benefits of whey protein.
Current research indicates no advantage of whey over casein in terms of
muscle growth. (Tipton, Med Sci Sports 36(12)2073, 2004) Yes, you can
buy commercial recovery foods that contain protein (Hammer Pro, Endurox
R4), but you can just as effectively enjoy cereal with milk, bagel with
peanut butter or pasta with meat sauce. These foods offer carbs with an
accompaniment of protein (a ratio of 40 gm carb, 10 gm pro). If you
prefer liquids for recovery foods, choose Instant Breakfast, chocolate
milk, Boost, yogurt or fruit smoothies; they are tasty sources of carbs
+ fluids + a little protein. The trick is to plan ahead and have the
right foods and fluids readily available…

Post-exercise Fluids

Preventing dehydration during exercise is preferable to treating
dehydration post-exercise. But if you failed to drink adequately (as
indicated by scanty, dark urine), you may need 24 to 48 hours to totally
replace this loss. Fruit juices, smoothies and watery fruits are better
than plain water because they offer carbs, protein, vitamins and other
nutrients that optimize recovery and invest in good health. If beer is
your preference, be sure to first quench your thirst with orange juice,
soft drinks or sports drinks and eat some carbs (pretzels, thick-crust
pizza) so you get carbo-loaded, not just “loaded”! Or think again. Would
you be wiser to simply enjoy the natural high of exercise?

Sports Nutritionist Nancy Clark RD counsels casual and competitive
athletes at her private practice in Healthworks, the premier fitness
center in Chestnut Hill MA (617-383-6100). Her Sports Nutrition
Guidebook ($23) and Food Guide for Marathoners ($20) offer abundant
fueling tips. To order: send check to PO Box 650124, W Newton MA 02465
or see

Nancy Clark, MS, RD
Sports Nutrition Services, Healthworks Fitness Center

Nancy Clark’s Sports Nutrition Guidebook, Third Edition
Food Guide for Marathoners: Tips for Everyday Champions

Books and sports nutrition teaching materials available at
TX and New Orleans workshop information:

1300 Boylston St., Chestnut Hill MA 02467
Phone: (617) 795-1875 Fax: (617) 795-1876

“Helping active people win with good nutrition.”

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