Fitness Article
of the Month
October 1997
This article,
written by Susan Kleiner, deals with nutritional requirements for
strength training and bodybuilding. Interesting stuff of some of
the ergogenic aids that actually do seem to work. Best of Health.
RM
Nutrition
for Muscle Builders
Susan M. Kleiner,
PhD, RD
THE PHYSICIAN
AND SPORTSMEDICINE - VOL 25 - NO. 8 - AUGUST 97
Athletes used
to think that if you wanted to bulk up your muscles, you just ate
a lot of calories. Bodybuilders were notorious for eating several
pounds of meat and up to a dozen raw egg yolks daily. Today we know
not only that high-fat, high-protein diets are unhealthy, but that
they don't promote lean tissue growth. The diet that will give you
the greatest increase in lean body mass without causing a lot of
fat gain is still high in calories--but the recommendations about
where these calories should come from have changed a lot.
Muscle-Building
Basics
Building muscle
requires tremendous energy, both to do the muscle-building exercise
and to build the tissue itself. One study (Gail Butterfield, PhD,
personal communication, January 1997) showed that each day strength-trained
athletes needed about 20 calories per pound of body weight (44 calories
[kcal] per kilogram [kg]) just to maintain their muscle mass--about
2,800 calories per day for a 140-pound person, 4,000 for a 200-pound
person (table 1). Apparently even more--25 to 30 calories per pound
of body weight (54 to 66 kcal/kg) per day--is required to build
muscle (1,2).
Carbohydrate.
Getting enough calories is important, but so is getting the right
kind of calories. Carbohydrate, stored in the body as glycogen,
is the predominant energy source for muscle-building exercise. The
harder and longer you work out, the more glycogen your muscles require.
Once your muscles are depleted of glycogen, you have no more energy
to continue your workout.
There are different
ways to figure out your carbohydrate needs, but the bottom line
is that with at least 500 to 600 grams of carbohydrate per day,
your muscles will stay packed with glycogen. One method is to base
your intake on 3.6 grams per pound of body weight (8 g/kg). At 4
calories per gram of carbohydrate, this means about 504 grams per
day or about 2,000
carbohydrate calories for a 140-pound person, and 720 grams or 2,900
carbohydrate calories for a 200-pound person.
A second strategy
for computing your carbohydrate needs is based on a percentage of
total calories. When total energy intake is below 4,000 calories
a day, getting 70% of those calories from carbohydrates will ensure
the muscle power and endurance required to strength train. With
a diet above 4,000 total calories a day, a lower percentage of calories
can be obtained from
carbohydrates, as long as you take in at least 500 to 600 grams
of carbohydrate.
Protein. At
this point you might be wondering, "What about protein?"
Protein is the basic building material for muscle tissue, and strength
trainers need to consume more than the rest of us. In the same study
that looked at energy needs, researchers found that during weight
lifting, those who ate enough calories required about 0.6 grams
of protein per pound of body weight (1.2 to 1.3 g/kg) daily to maintain
muscle mass. If the intensity of the exercise was increased to build
muscle, the daily requirement went up to almost 0.7 grams per pound
(1.5 g/kg).
Based on a
wide review of scientific data (3), current daily protein recommendations
for serious strength trainers are about 0.6 to 0.8 grams per pound
(1.4 to 1.8 g/kg). This equals 90 to 115 grams of protein per day
for the 140-pound strength trainer and, 128 to 164 grams for the
200-pounder.
Fat. Once you've
determined your carbohydrate and protein needs, all the leftover
calories--less than 30% of total calories--can come from fat. To
keep your heart healthy, make sure that most of your fat calories
are from unsaturated fats.
Water
Needs
Next on the
list of important nutrients is water. Good hydration is just as
essential for strength training as it is for endurance training.
Your body requires at least eight 8-ounce cups of caffeine-free,
nonalcoholic fluids every day. You need to drink even more to replace
fluids that are lost during exercise.
Make sure you
go into your workouts well hydrated by drinking 2 cups of fluid
2 hours before exercise. During exercise, drink 4 to 8 ounces every
15 to 20 minutes. After exercise, replace any further fluid losses
with 16 ounces of fluids.
Another approach
is to weigh yourself before and after exercise: Any weight lost
is fluid. Replace every pound lost with at least 16 ounces of fluid.
Supplement
Sense
Most supplements
that are supposed to help build muscle don't work. But some, such
as creatine, fluid and electrolyte replacers, carbohydrate supplements,
and liquid meal replacers may offer some benefits to strength training
athletes.
Creatine. In
the past several years, creatine has gained attention among athletes
because it has the potential, when combined with a good diet and
strength training program, to produce slightly more power during
workouts. In addition, loading creatine into the muscles may help
speed up muscle gain.
Meat is the
best dietary source of creatine, and vegetarians generally have
lower muscle creatine concentrations than meat-eaters. People at
the lower end of the normal range for muscle creatine are the most
likely to benefit from supplementation.
The usual dosage
for creatine loading is 5 grams of creatine monohydrate four times
per day for 5 days. A maintenance dose of 2 grams per day can follow.
Taking more than the usual dosage of creatine offers no added benefit.
Also, users should be aware that creatine and other popular supplements
are subject to little government regulation, so there is no guarantee
that they are
pure.
Sports drinks.
Fluid and electrolyte replacers are beneficial if exercise lasts
longer than 1 hour. Carbohydrate supplements can be useful to help
fit adequate carbohydrates into a busy day. Additionally, one study
(4) indicated that by taking creatine with 17 ounces of liquid carbohydrate
supplement, muscle creatine concentrations can be boosted by up
to 60%.
Consuming a
meal-replacement beverage just after muscle-building exercise may
be a convenient way to help stimulate muscle growth. Protein and
carbohydrates trigger the release of insulin and growth hormone,
which are integrally involved in muscle growth. Meal replacement
beverages are also great for adding well-balanced calories when
you just don't have the time to eat a meal.
Don't
Forget Sweat
Even though
supplement purveyors promise easy results, gaining muscle takes
determination, a good diet, and lots of sweat. Stick to it, and
you'll be pleased with your results.
References
1. |
Manore
MM, Thompson J, Russo M: Diet and exercise strategies of a world-class
bodybuilder. Int J Sport Nutr 1993;3(1):76-86 |
2. |
Kleiner
SM, Calabrese LH, Fiedler KM, et al: Dietary influences on cardiovascular
disease risk in anabolic steroid-using and nonusing bodybuilders.
J Am Coll Nutr 1989;8(2):109-119 |
3. |
Lemon PW:
Do athletes need more dietary protein and amino acids? Int J
Sport Nutr 1995;5(suppl):S39-S61 |
4. |
Green AL,
Hultman E, Macdonald IA, et al: Carbohydrate ingestion augments
skeletal muscle creatine accumulation during creatine supplementation
in humans. Am J Physiol 1996;271(5 pt 1):E821-E826 |
Remember, you,
your physician, and your nutritionist need to work together to discuss
nutrition concerns. The above information is not intended as a substitute
for appropriate medical treatment.
Dr. Kleiner
is a private nutrition consultant to athletes in the Seattle area.
She is a member of the American College of Sports Medicine; a member
of the American Dietetic Association and its practice group, Sports
and Cardiovascular Nutritionists (SCAN); and a fellow of the American
College of Nutrition.
This fitness
article is for educational purposes only. It is not medical advice
and is not intended to replace the advice or attention of health-care
professionals. Consult your physician before beginning or making
changes in your diet, supplements or exercise program, for diagnosis
and treatment of illness and injuries, and for advice regarding
medications. Thanks. RM
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