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For years bodybuilders have asserted that they need more protein than average people, and all the while nutritionists
have kindly replied, "No, you don't." Most of the scientific studies show that athletic activity does not appreciably
increase protein requirements. Could it be that bodybuilders really don't need any "extra" protein? Think about this
for a minute: Muscle is about 75 percent water, so a pound of muscle contains only about 100 grams of protein. Most
people would consider gaining 10 pounds of muscle a year to be good progress, and that would amount to 1,000 grams of
protein. Over a year's time that works out to gaining 2.74 grams of protein per day, which is about one or two bites
of a chicken breast. So, they say, eat a couple of extra bites of chicken breast and that's enough protein to grow as
big as Arnold.
Bodybuilders, on the other hand, have said that if they want muscles twice as big as everybody else they have to eat
twice as much protein as everybody else. They need extra protein to supply the building blocks to build extra muscle.
Well, neither party turns out to be exactly right. Bodybuilders do need more protein than average people, but not for
the reason they thought. In fact, those two extra bites of chicken every day would be enough to grow muscles as big as
Arnold's - if it all ended up being converted to muscle. The problem is, it doesn't.
The original studies looking at protein requirements of athletes were flawed in several ways. First, they used untrained
athletes and the exercise protocols were not very intense. The subjects simply did not exercise long enough or hard enough
to see an effect of exercise on protein requirements. Second, in the old studies nitrogen lost in sweat was not measured,
and this turns out to be significant.
A little background: What bodybuilders seek to achieve is a state of positive protein balance. They want more protein
coming into the body than is leaving. Protein is on average about 16 percent nitrogen by weight. Since nitrogen is easy
to measure in the lab, nitrogen balance is used as a way to measure protein balance. Nitrogen is also a good way to keep
track of the protein economy in the body because carbohydrate and fat do not contain nitrogen. When we eat excess protein,
it can he stored as muscle, but it could also be converted to fat. If it is converted to fat, the nitrogen is removed as
ammonia and is excreted in the urine after the ammonia is converted to urea. This process leaves the carbon skeleton of
the amino acids, which can be broken down and used to make fat. By measuring nitrogen balance, we see how much nitrogen
is entering the body and how much is leaving. Any that remains in the body must represent new protein tissue.
The old studies that measured nitrogen balance in athletes looked at how much nitrogen was consumed as protein in the diet
versus how much nitrogen was excreted. They found that athletes could remain in nitrogen balance without eating much, if
any, extra protein. This is the basis for the long-standing disagreement between bodybuilders and nutritionists.
During the last few years a number of important studies have been performed showing that hard-training athletes may actually
need vastly more protein than average people. The new experiments also measure nitrogen lost in sweat, which the older
studies failed to do. Also, the new experiments are much more realistic, using experienced athletes in intense training
programs. A significant amount of nitrogen can be lost in sweat, and if this is factored in, intense-training athletes may
need two or three times as much protein as an average person to maintain nitrogen balance.
Do athletes need more protein? Yes, definitely, they need significantly more protein than sedentary people. The controversy
is over on this matter. Now even the old- school nutritionists agree. Do bodybuilders need more protein so they can have
more substrate to build new muscle tissue? No, they need more protein because they excrete more nitrogen during exercise.
Very little extra protein is needed to build new muscle tissue, but a lot of extra protein is needed to make up for that
which is burned as fuel during exercise.
The branched-chain amino acids, (BCAA's) are of special importance to athletes because they are metabolized in muscle
rather than in the liver. Researchers estimate that about one-third of all the amino acids entering the liver from the
portal vein are used for protein synthesis by the liver (serum proteins) or are converted to glucose or used for energy by
the liver. Thus a high- protein meal only increases serum amino-acid levels by about 20 percent.
Well, so what, and what does all this have to do with bodybuilding? The liver does not have the enzymes to metabolize the
BCAA's, and this means that the BCAA's increase markedly in the bloodstream after a meal. (They pass straight through the
liver without being broken down.) In fact, the BCAA's can account for about 70 percent of the amino acids released from the
small intestine via the liver to the rest of the body.
Are you starting to get the idea that the branched-chain aminos are important in muscle protein metabolism? Indeed, we
know that BCAAs account for 50 to 90 percent of the amino acids taken up by muscle tissue in the three hours following a
protein meal. The branched-chain aminos are also effective at stimulating insulin secretion, which in turn stimulates
So what's the bottom line here? First off, BCAA's account for 50 to 90 percent of the amino acids taken up by muscle after
a protein meal. Once there, they are available to serve as substrate for protein synthesis. They increase insulin, further
stimulating protein synthesis. This is their anabolic effect. During periods of intense exercise they can be burned for
energy, helping prevent breakdown of muscle tissue to use as fuel. This is their anti-catabolic effect.
You can see why supplementation with branched-chain amino acids is a good practice. The best way to use it is to take it
with meals, and to eat six small meals per day. The most important times to take it are the meal before your workout and
the meal after your workout. Combine these supplements with a healthful diet adequate in calories and protein, and I think
you've got the best muscle-building program modern science has to offer.