Nutrition Performance - Protein Requirements of Bodybuilders: A 2004 Update

“Athletes need the same amount of protein foods as non-athletes. Protein does not increase strength." —Journal of the American Medical Association in 1978

Historically, bodybuilders and other strength-power athletes have always consumed a lot of protein. High-protein diets are used simply because they work. And even though there have been desperate attempts to discourage it (“high-protein intake has no effect on muscle mass, will shrink your penis and explode your testicles), the popularity has not waned. The term “protein requirement” means the amount of protein that must be consumed to provide the amino acids for the synthesis of those body proteins irreversibly catabolized in the course of the body´s metabolism. The recommended allowances (RDA) for protein (nitrogen) are based upon experiments in which the normal requirement is defined as the intake necessary to achieve zero balance between intake vs. output.¹ Thus, the intake of nitrogen from protein must be sufficient to balance that excreted; this concept is called nitrogen balance.

However, serious gym rats are different animals. They are not concerned with nitrogen balance, but rather on their absolute gains in muscle mass and strength. Unfortunately, some malcontent mavericks still claim protein requirements of athletes simply refer to the minimum amount of dietary protein necessary to sustain health. Thus, it’s time to set the record straight.

Historical Overview of Protein Requirements

Dr. Cathcart, in an extensive review of literature prior 1925, concluded that “Accumulated evidence seems to me to point to unmistakable fashion the opposite conclusion that muscle activity does increase, if only in small degree, the metabolism of protein.”¹ Further, experiments conducted in the 1940s demonstrated that supplemental protein could enhance muscle mass if taken by power or strength athletes.¹³ Unfortunately, in 1989, the U.S. Food and Nutrition Board claimed that any increased need for protein induced by exercise does not exceed the safety buffer included in the current RDA (0.8 grams/kilogram/day).² Of course, that´s nonsense, since the RDA is based on experiments completed on subjects who did not engage in regular exercise.

In 1992, Dr. Peter Lemon wrote: “Although these studies clearly suggest that protein needs of strength or speed athletes exceed current recommendations, the absolute values [1.2-2.0 g/kg/day] fall considerably below the intakes reported by many strength athletes, especially bodybuilders. This discrepancy could be explained if nitrogen balance measures are insufficient to completely assess the value of high-protein diets. These athletes are not concerned with nitrogen balance, but rather on their absolute gains in muscle mass and strength… Perhaps a highly positive nitrogen balance when combined with powerful anabolic stimulus

of heavy resistance exercise can enhance protein synthesis and/or reduce protein degradation resulting in greater gains in mass and strength.”³

Further, in 2000, Dr. Lemon pointed out that “it is possible that even if a measure like nitrogen balance does not indicate an increased protein requirement, exercise performance could still be enhanced by a greater protein intake, i.e., the additional protein might alter a metabolic process enhancing energy utilization for endurance exercise or could stimulate anabolism resulting in greater muscle mass and/or strength gains.”⁴

In 2002, this author wrote: “It is important to keep in mind that the words "need" or "requirement" as they frequently appear in this paper does not simply refer to the minimum amount of dietary protein necessary to sustain health, but to the amount of protein necessary to optimize exercise performance, while not compromising other dietary or health aspects.”⁵

Finally, according to recent paper by Drs. Kevin Tipton and Robert Wolfe, “Accepted definitions of protein requirements are based on nitrogen balance measures in laboratory and may have no relationship with athletic performance. Athletes and coaches are more interested in the optimum protein intake for athletic success, rather than actual definition of protein requirement based on nitrogen balance… There are no nitrogen balance studies that show other than increased positive nitrogen balance when protein intake is increased. Interpreted this way, it could be argued that athletes who desire muscle hypertrophy should eat very high protein diets to maximize their muscle gain. ”⁶

Thus, I recommend a minimum of one gram of protein per pound of body weight for hardcore bodybuilders. Many professional bodybuilders take in two to three grams of protein per bound of body weight. However, it has been estimated that 90 percent of male professional bodybuilders use anabolic-androgenic steroids at any given time. (No shit, Sherlock?!). It is certainly possible that the extremely high-protein intakes consumed by some bodybuilders are only advantageous when combined with these agents.

Although not always appreciated by “sports nutrition traditionalists,” amino acids alone, or in various combinations, can have specific pharmacological effects (e.g., hormones, neurotransmitters, immunomodulation, control of protein turnover, etc.). Despite the potential benefits of many amino acids, the use of amino acid supplements needs to be more systematically investigated. Clearly, we need more scientific evidence to fine-tune the use of amino acid supplements.

Protein and Weight-Loss

Counter to the current U.S. Dietary Guidelines which promote a diet high in complex carbohydrates, recent clinical investigations support the efficacy of high-protein diets for weight loss/fat loss, as well as for improved insulin sensitivity and blood lipid profiles. Thus, the popularity of high-protein diets for weight loss is unquestionable.

Protein is the macronutrient generally associated with increased satiety and voluntary reduction in energy consumption has been noted in subjects consuming high-protein meals compared with high-carbohydrate meals. For example, in a recent well-controlled study by Dr. Carol Johnston and co-workers at Arizona State University, healthy adults were randomly assigned to one of two low-fat (less than

30 percent energy), energy-restricted groups: high-protein (30 percent energy) or high-carbohydrate (60 percent energy). During six-week trial, 24-hour intakes were strictly controlled.¹² Interestingly, two subjects in the high-carbohydrate group withdrew from the trial due to “extreme hunger.” In addition, only the high-protein regimen resulted in a marked positive nitrogen balance.

Is a High-Protein Diet Lethal? No!

Some well-meaning but misinformed nutrition “authorities” claim high-protein diets possess significant health risks. For example, the American Heart Association´s (AHA) Nutrition Committee claims, “Individuals who follow these [high-protein] diets are at risk for… potential cardiac, renal, bone and liver abnormalities overall.”⁷ Liver abnormalities? That´s physiological nonsense! Protein is needed not only to promote liver tissue repair, but also to provide lipotropic agents such as methionine and choline for the conversion of fats to lipoprotein for removal from the liver, thus preventing fatty infiltration.⁹ And when it comes to kidney function, there are no data in the scientific literature demonstrating that healthy kidneys will be damaged by the increased demands of protein consumed in quantities above the RDA.⁹ Furthermore, real world examples support this contention since kidney problems are nonexistent in the bodybuilding community in which high-protein intake has been the norm for over half a century.⁸

The AHA Nutrition Committee also suggests that high-protein intake may increase blood pressure. However, there is no scientific evidence whatsoever supporting this contention. In fact, a negative correlation has been shown between protein intake and systolic and diastolic blood pressures in several epidemiological surveys.⁹ Further, the AHA Nutrition Committee claims that high-protein intake has detrimental effects on bone health. Hmm… Guess what? Dietary protein increases circulating IGF-1, a growth factor that is thought to play an important role in bone formation. Indeed, several studies have examined the impact of protein supplementation in patients with recent hip fractures. For example, Dr. M.A. Schurch and colleagues reported that supplementation with 20 grams of protein per day for six months increased blood IGF-levels and reduced the rate of bone loss in the contralateral hip during the year after the fracture.¹¹

Finally, the AHA Nutrition Committee ignores the fact that energy restriction increases protein requirements. It has been known for about a half century that inadequate energy intake leads to increased protein needs.⁹ For example, Dr. G.E. Butterfield has shown that feeding as much as two grams of protein per kilogram per day to men running five or 10 miles per day at 65 to 75 percent of their VO_2max is insufficient to maintain nitrogen balance when energy intake is inadequate by as little as 100 calories per day.¹⁰ Thus, when trying to lose weight, it is important to keep protein levels high. The reduction in calories needed to lose weight should be at the expense of the fats and carbohydrates, not protein.¹

Obviously, the AHA Nutrition Committee´s statement on dietary protein contains misleading and incorrect information. Certainly, such public warnings should be based on a thorough analysis of the scientific literature, not unsubstantiated fears and misrepresentations. For individuals with normal kidney function, the risks of high-protein intake are minimal. (See my recent scientific paper in Metabolic Syndrome and Related Disorders⁹). However, consumption of