When we fast-forward to the era of the sixties and seventies we find there
was a renewed hype about protein being some sort of miracle food. This was due, largely, to the muscle magazines of the era which pushed protein and claimed it could make you grow as big as a god! As a result, many bodybuilders and strength trainers started to consume large quantities of whole milk, meat and eggs. (Let’s not forget the raw eggs—thanks to "Rocky Balboa".) During the 90's and into the present we've seen protein powders promoted as the new wonder-drug. Ads and commercials continue to tempt consumers to purchase protein powders in garbage can-sized quantities. And we've been mesmerized by a constant flow of ultimate protein shakes that will supposedly help pack on muscle mass at almost the same rate as Anabolic Steroids.

Clearly, science is being placed on the back shelf, and this has resulted in a host of myths and fallacies springing up in the field of sports nutrition. It's no surprise that there's so much conflicting information and plain misinformation floating around. On one side we have the nutritional, dietetic and medical community laying blame on the bodybuilders, weightlifters and strength trainers for perpetrating the myth that strength athletes need to consume above and beyond the RDA (Recommended Dietary Allowance) of 0.8 grams per kilogram of lean bodyweight (1 kilogram=2.2 pounds). Then we have the bodybuilders and strength trainers holding the nutritionists, dieticians and medical community responsible for bad information. The question remains, what is the optimal protein intake required for weightlifters, bodybuilders, strength trainers and other athletes?

Protein's Role

Protein is a complex chemical structure of carbon, nitrogen, hydrogen and oxygen. Accounting for 50% of the body's dry weight, it has been estimated that humans consist of 50,000 different proteins. From the simple blink of an eye to the flow of blood to muscles under extreme stress, proteins are everywhere. Their function involves more than muscle tissue repair. It includes repair of red blood cells, hair and fingernail growth, regulation of hormone secretion, movement (muscle contraction), digestion, maintenance of the body's water balance, protection against disease, transport of nutrients to and from cells, the carrying of oxygen and regulation of blood clotting. So the role of protein is very important to over-all body function and health. Sadly enough, this role has been improperly depicted in various muscle magazines, on TV fitness shows and in claims by trainers and bodybuilders who think protein is mainly used to repair damaged muscle tissue. This couldn't be further from the truth.

Protein Intake

As mentioned earlier, the RDA is 0.8 grams per kilogram of lean bodyweight (U.S. Food and Nutrition Board, 1980) for sedentary adults. For infants and children the RDA is doubled and tripled because of the rapid growth rate they experience. How did the researchers come up with this RDA and arrive at the figure that has been shunned by the bodybuilding community? Studies using nitrogen (a component of protein). have been conducted to see how much protein is used and absorbed before an excess condition results. Researchers looked at the nitrogen balance and made comparisons to see if a positive or a negative balance had been occurring. They observed the outcome by comparing the amount of nitrogen excreted with the amount ingested, and then they determined whether or not protein was accumulating in the body, remaining at the same level, or decreasing.

The nitrogen balance test uses nitrogen loss in the form of sweat, urine, feces, shedding of skin, and loss of hair on a day-to-day basis. If there is a positive balance in nitrogen levels, it means there has been more nitrogen ingested than excreted, and so, tissue growth can be a direct result. A negative balance shows researchers that more nitrogen is being excreted than taken in, and this means, of course, that more protein is being lost than produced. Basically, the protein requirement for sedentary adults involves replacing routine losses—the task, so to speak, is to keep the leaky bucket topped up.

So why did researchers in North America come to the conclusion that the RDA is only a rationed 0.8 grams per kilogram? Well it seems they concluded that 0.36 grams per kilogram of lean bodyweight in protein is lost per day. With a safety margin in place, it has been bumped up to 0.45 grams per kilogram of lean bodyweight, and then bumped up again to approximately 0.75 grams per kilogram. This is to replace the amount which may be lost during digestion, as well as making up for a lack in quality of protein. The general protein requirement for sedentary adults is just enough that if one follows this guideline they will supply themselves with enough amino acids to replace each day's loss without allowing for exercise and the growth of muscle tissue. It's ironic that the RDA for children (who are experiencing growth) is greater than the RDA for adults. The Academy of Sciences and the nutrition board insist that exercise (which leads to musculo-collagenous hypertrophy among other changes in the body) doesn't generate an increase in one's protein requirements (1). Note that RDA can vary from place to place; Russia, Denmark, and Britain have different RDA standards.

Exercise adds a new dimension to the issue because the body, with an increased need for protein, has to rely heavily upon dietary sources rather than draw from it's own stores. If this need is not met during exercise then the body will start to draw upon its muscle tissue as a source. Though it may seem that humans don't need much protein, the facts haven't been established as to how much an exercising individual should be taking in. Recent research shows that the RDA doesn't appear to meet the needs of exercising adults. One of the top researchers in this field, Dr Peter Lemon, stated in a recent review paper that, "the RDA for those engaged in strength training should be about 1.7 – 1.8 grams of protein per kilogram of body mass per day". Dr Lemon came to this conclusion after citing several studies (Fern, 1991, Tarnopolsky et al., 1992) which used amounts of protein ranging from 1.3 – 3.3 grams of protein per kilogram of bodyweight. At Kent University researchers tested 3 different groups of people: 1) on a low protein diet which was 0.9 grams of protein per kilogram of bodyweight; 2) another group eating 1.4 grams of protein per kilogram of bodyweight; and 3) a group eating 2.4 grams of protein per kilogram of bodyweight. Both sedentary and strength training groups were involved. The results showed that 1.4 grams resulted in protein synthesis while there were no changes in the low protein group and, finally, the group that ingested 2.4 grams of protein did not see any more increased protein synthesis than the 1.4 grams of protein group.

Another study conducted at the Letterman Army Institute of Research in San Francisco showed that subjects on a higher protein intake (2.8 g/kg/day), coupled with intense strength training, gained a whopping 3.28 kg (7.2 lbs) of lean mass. The study was done over a 40-day period and the subjects were trained to near exhaustion (2). Another study of weightlifters over a 3 month period, with the protein increased from 2.2g/kg/day to 3.5 g/kg/ day, resulted in a 6% increase in muscle mass and a 5% increase in strength (3). Susan M Klieiner, who holds a PhD in nutrition and human performance from Case Western Reserve University, states in her book, Power Eating, that for muscle building an intake of 1.6-2.2 grams per kilogram of bodyweight is recommended. Dr Michael Colgan, in Optimum Sports Nutrition, claims that the RDA doesn't meet the needs of athletes who train in an intense fashion. So, the evidence provided by some of the highly regarded "experts" in this field indicates that the addition of extra protein has been shown to display positive effects which produce muscle growth.