Protein 101: What is protein anyway?
Its not surprising that bodybuilders put so much emphasis on protein. After all, protein is construction material for the human body like bricks are for a building. Body structures made from protein include skin, hair, nails, bones, connective tissue and of course skeletal muscle. Other proteins in your body include antibodies, enzymes, hormones such as insulin, and transporters such as hemoglobin. Next to water, protein is the most abundant substance in the body, making up approximately 15-20% of your weight. Of most interest to the bodybuilder is the fact that 60-70% of all protein in the body is located in the skeletal muscles. In order for muscle growth to occur, every day you must consume more protein than your body utilizes.
Like fats and carbohydrates, proteins are also composed
of carbon, hydrogen and oxygen. The difference is nitrogen.
Only protein can bring nitrogen into the body. Because muscle
tissue contains most of the body's protein and protein contains
nitrogen, scientists can study the effect of dietary protein
on muscle growth by comparing the amount of nitrogen consumed
with the amount excreted (in feces, urine and sweat). If
the intake of nitrogen is greater than the amount excreted,
then we know that protein is being retained and new muscle
is being synthesized. This is known as positive nitrogen
balance. If more nitrogen is excreted than consumed, you
are in negative nitrogen balance, indicating that protein
is being broken down and muscle is being lost.
Amino acids: The building blocks of protein
The smallest units of a protein are called amino acids. Like bricks in a wall, amino acids are the building blocks of protein. Just as glycogen is formed from the linkage of numerous glucose molecules, proteins are formed from the joining of numerous amino acids. There are 20 amino acids that are required for growth by the human body. From these 20 amino acids, there are tens of thousands of different protein molecules that can be formed. Each protein is assembled from the bonding of different amino acids into various configurations. Growth hormone, for example, is a protein chain of 156 amino acids.
"Amino acids are somewhat like letters in the alphabet. If you had only the letter G, all you could write would be a string of Gs: G-G-G-G-G-G-G-G. But with 20 different letters available, you could create poems, songs, or novels. The 20 amino acids can be linked together in an even greater variety of sequences than are possible for letters in a word or words in a sentence. The variety of possible sequences for polypeptide chains is tremendous." -Eleanor Whitney and Sharon Rolfes, "Understanding Nutrition."
Essential vs. Non-essential amino acids
Out of the twenty amino acids, the human body can make eleven of them. These are called the non-essential amino acids (also known as "dispensable amino acids). The other nine amino acids are called "essential amino acids" or (indispensable amino acids). Essential amino acids are those which cannot be manufactured by your body and must be supplied from your food.
Essential (indispensable) amino acids
Histidine
Isoleucine
Leucine
Valine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Non essential (dispensable) amino acids
Alanine
Arginine
Asparagine
Aspartic Acid
Cysteine
Glutamic acid
Glutamine
Glycine
Proline
Serine
Tyrosine
Why bodybuilders must eat "complete" proteins every three hours
Foods that contain a balanced combination of all the essential and nonessential amino acids in the exact amounts required by the body for growth are called "complete proteins." In order for the body to synthesize muscle, all the essential amino acids must be available simultaneously. Any non-essential amino acids that are in short supply can be produced by the liver, but if an essential amino acid is missing, the body must break down its own proteins to obtain it. To prevent muscle cell breakdown, dietary protein must supply all the essential amino acids. If your diet is missing any essential amino acids, protein synthesis will be inhibited.
Carbohydrates have a storage depot in the body called glycogen. Glycogen can be stored in the muscles and liver and then drawn upon hours or even days later when it is needed. Proteins cannot be stored in the body. There is only a very small and transient amino acid pool in the bloodstream. To maintain the optimal environment for muscle growth (positive nitrogen balance), complete proteins must be eaten with every meal. This explains the rationale behind the common bodybuilding practice of eating six protein-containing meals per day (one about every three hours.)
Protein Quality: Complete vs. Incomplete proteins
Protein isn't just found in meat, eggs and milk. There is also protein in vegetables, beans, legumes, and grains. However, the protein in these foods is not considered "complete" because it lacks one or more of the essential amino acids. Generally speaking, proteins from vegetable sources are lower in quality and that's the reason they are eschewed by bodybuilders. The complete proteins are those that come from animal sources such as eggs, milk and meat.
Many grains and legumes contain substantial amounts of protein, but none provide the full array of essential amino acids. Beans, for example, are very high in protein with about 15 grams per cup, however, they are missing the essential amino acid Methionine. Similarly, grains are lacking the essential amino acid Lysine. It has been frequently pointed out that combining two incomplete sources of vegetable protein such as rice and beans provides you with the full complement of essential amino acids. This may be true, but there's a decided difference between simply meeting your minimum amino acid requirements for health and consuming the optimal quality of protein for building muscle. Combining complementary vegetable sources of protein just doesn't cut it for the serious bodybuilder.
Is "Vegetarian bodybuilder" an oxymoron?
A pure vegetarian (vegan) diet is not conducive to building muscle. One thing you will never see is a rock-hard, massive and muscular vegan. Lacto-vegetarians (those who use dairy products) and ovo-lacto-vegetarians (those who use eggs and dairy products) can build excellent physiques. Bodybuilding champion Bill Pearl is just one example. Pearl is well known for his lifelong aversion to eating meat, but he does use complete proteins from eggs or dairy products. With this semi-vegetarian approach, Pearl won the Mr. America and Mr. Universe tittles and became a legend in the bodybuilding and fitness world.
The bottom line is that you can get fit and healthy without consuming animal proteins, but unless you include eggs or dairy products, you will never develop a physique worthy of the bodybuilding stage. If a hard and muscular physique is what you're after, then heed the advice of Robert Kennedy, publisher of Muscle Mag International and author of "Rock Hard, Supernutrition for Bodybuilders:"
"The bodybuilder would be ill-advised to adopt a true vegetarian diet. You can be one of the millions who are eating less meat and more vegetables. You may even want to drop all flesh entirely. But is would be a mistake to try for pure vegetarianism. Only 3.7% of Americans consider themselves to be vegetarians, and of those only a fraction of 1% are purists. In the bodybuilding world of champions, that percentage is currently.... ZERO!"
Lean sources of complete proteins
Complete proteins come from animal sources including meat, eggs and dairy products. The obvious problem with animal proteins is that they also contain large amounts of saturated fat. To stay lean, bodybuilders must always keep fats in the diet low. Fortunately, fat from animal proteins can easily be avoided simply by making the correct choices. For example, use egg whites instead of egg yolks, lean meats such as turkey breast and chicken breast instead of fatty cuts of meat, and 1% low fat or non-fat dairy products instead of whole milk dairy products. These are some of the best sources of lean protein for bodybuilding purposes:
Chicken breast
Turkey breast
Fish
Shellfish (shrimp, lobster, crab, clams, etc)
Egg whites
Lean red meats (top round, lean sirloin, and flank)
Nonfat or low fat dairy products
Protein powders (Whey protein, for example).
The great debate; The RDA vs. the "protein pushers"
For years a heated controversy has raged over whether or not extra protein will boost muscle development. On one side of the debate you have the conservative dietitians and medical community who stubbornly insist that the recommended Daily Allowance (RDA) is all you need to develop muscle. The RDA's are the official government guidelines set by the national research council. Currently the RDA for protein is based on body weight and is set at .8 grams per kilogram of body weight (that's .36 grams per lb. of body weight). For a 172 lb. man that equates to a paltry 62 grams per day. It is important to note that the RDA's were developed for the "average" sedentary person to avoid deficiency, not for athletes in hard training to gain muscle and strength. In fact, the RDA handbook even says, "no added allowance is made for stresses encountered in daily living which can give rise to increases in urinary nitrogen output."
On the other side of the debate, you have the "protein pushers" who claim that megadoses of protein are the key to muscular growth. These high protein fanatics often suggest intakes of 400-500 grams a day or more. More often than not, the protein pushers are in some way affiliated with a supplement company and have a vested interest in selling you protein powder. In other cases, these high protein advocates may be professional bodybuilders who are taking large amounts of anabolic steroids, which can allow the body to utilize more protein than normal.
So who is right, the conservative medical and scientific community or the protein pushers? The answer is neither; the optimal intake is clearly somewhere in between the two extremes. An "optimal" protein intake for bodybuilders is still unknown at this time and will require further research, but one thing is for certain: The RDA is not enough to support the added requirements for intense bodybuilding training. Even the RDA handbook itself says, "No added allowance is made here for stresses encountered in daily living which can give rise to transient increases in urinary nitrogen output. It is assumed that the subjects of experiments forming the basis for the requirement estimates are usually exposed to the same stresses as the population generally." If bodybuilding isn't an "unusual stress" beyond what is normally encountered in daily living then I don't know what is.
What the current research says about protein and bodybuilding
Research has conclusively proven that exercise increases protein needs. Dr. Peter Lemon is the world's leading researcher on protein requirements and athletes. In the journal "Medicine and Science in Sports and Exercise" (19:5, S179-S190,1986) Dr. Lemon writes;
"Several types of evidence indicate that exercise causes substantial changes in protein metabolism. In fact, recent data suggests that the protein recommended dietary allowance might actually be 100% higher for individuals who exercise on a regular basis. Optimal intakes, although unknown, may be even higher, especially for individuals attempting to increase muscle mass and strength."
Dr. Lemon's most recent research published in "Nutrition Reviews," (54:S169-175, 1996) indicates that strength athletes need up to 1.8g of protein per kg. of body weight to maintain positive nitrogen balance. That's .8 grams per lb. of body weight or almost 140 grams a day for someone who weighs 172 lbs. This is very close to the long-held belief of bodybuilders that 1 gram per pound of body weight is optimal. Some studies have shown that even higher protein intakes may be necessary in hard training strength athletes. In one study of Polish weightlifters (Nutr. Metabolism 12:259-274), 5 of 10 athletes were still in negative nitrogen balance even while consuming 250% of the RDA.
So much research has been done on protein and athletes that it's amazing that so many conservative registered dietitians and medical professionals still cling to the outdated notion that the RDA for protein is sufficient for muscle growth. The biggest irony is the fact that many of these "RDA pushers" are overweight, flabby, out of shape professors, researchers or white lab coat types. I don't know about you, but I have a very hard time taking advice from "armchair experts" who don't walk the walk. After years of being criticized by the academic and scientific communities for their "excess" protein intakes, bodybuilders today have received their vindication; It is no longer a theory that protein intakes higher than the RDA are more effective for building muscle, it is now scientific fact.
Now that we've established these facts, that still leaves one burning question: How do you determine the precise amount of protein that is right for you? Read part two to find out.
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