By Dr. Dwayne N. Jackson, Ph.D.

If I had to choose one supplement to have in my “bodybuilding toolbox” and nothing else, it would definitely be high quality [1] protein . Let’s face it, it is relatively affordable, it promotes anabolism, promotes fat-loss, it abolishes catabolism, and scientific research is finding more and more reasons to make it a staple in everyone’s cupboard. [2] Protein has stood the test of time and has acquired the status of “jack of all trades” based on one simple fact…. it works!

A recent and eloquent paper published in the International Journal of Obesity (Nature Publishing Group) clearly outlines the importance of [3] protein in the management of body-weight. In fact, their title sums it up perfectly, “Dietary [4] protein , metabolism, and body-weight regulation: dose-response effects” (Westerterp-Plantenga et al., 2006). The following is a brief, but cutting edge outline of why [5] protein supplementation is a must for anyone seeking a lean muscular physique:

• In terms of satisfying hunger, [6] protein ranks highest of all macronutrients. In fact, subjects on high-[7] protein hypocaloric diets often report greater satiety and overall satisfaction than those on lower-[8] protein (higher-carbohydrate) diets (Johnston et al., 2004;Layman et al., 2003;Layman et al., 2005). It is well documented that keeping food cravings to a minimum is integral to the success of a diet.
  



• The calculated metabolizable energy from [9] protein is 17 kJ/g, however the actual measured net energy yield is 13 kJ/g. The discrepancy lies in the thermogenic effect of [10] protein ingestion, which takes into account the amount of energy needed to break-down [11] protein s; thus, it takes more ATP to metabolize and store [12] protein s than any other macronutrient (Westerterp-Plantenga et al., 2006). Interestingly, it has been also shown that the potent thermic increase is related to the high ATP cost of increased [13] protein synthesis after ingesting [14] protein (Tessari et al., 2003;van Milgen J., 2002). The metabolism of the [15] protein source directly impacts the expenditure and it’s subsequent thermic effect after ingestion (Westerterp-Plantenga et al., 2006). Thus, the absorption rate of the [16] protein is directly related to its thermic effect on the body. Science supports this claim (Boirie et al., 1997;Dangin et al., 2001;Dangin et al., 2002), as such, hyrodrolysed whey [17] protein and whey [18] protein isolates (preferably CFM WPI) result in a more robust thermic effect than does whey concentrate or casein [19] protein . (For more information on [20] protein sources and absorption rates, [21] see our [22] protein source guide.
  



• High-[23] protein diets result in a decrease in the ratio between fat-mass and fat-free-mass. Buchholz and Schoeller conducted a thorough meta-analysis and reported that high-[24] protein diets resulted in approximately (or greater than) 6 lbs more weight loss after 12 weeks of treatment (Buchholz & Schoeller, 2004). Numerous well designed studies, conducted on obese populations, have shown that higher-[25] protein diets result in a greater loss of fat-mass while maintaining lean (muscle) mass, even while in caloric deficit (Farnsworth et al., 2003;Foster et al., 2003;Johnston et al., 2004;Layman et al., 2005;Layman et al., 2003;McAuley et al., 2005).
  



• Those who achieve their lean physique through high-[26] protein diets tend to maintain their fat-loss better than others. This is due to a positive shift in metabolic profile (based on healthy body composition). It has been shown that in the weight-maintenance phase of a diet, when one may observe a slight increase in body-weight, the extra pounds tend to be due to increased fat-free-mass (Westerterp-Plantenga et al., 2006).
  

It is clear that maintaining high-[27] protein intake is a huge benefit to fat-loss while dieting. Bodybuilders have known this anecdotally for years, but recent science provides us with solid evidence for making it a base macronutrient in our fat-loss strategy. After all, high-[28] protein ingestion curbs your appetite, increases thermogenic lipolysis, decreases fat-mass, maintains hard-earned muscle-mass, and maintains fat-loss upon completion of the diet. Indeed, [29] protein is the “jack of all trades”.

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REFERENCES:

References

Boirie Y, Dangin M, Gachon P, Vasson MP, Maubois JL, & Beaufrere B (1997). Slow and fast dietary [30] protein s differently modulate postprandial [31] protein accretion. Proc Natl Acad Sci U S A 94, 14930-14935.

Buchholz AC & Schoeller DA (2004). Is a calorie a calorie? Am J Clin Nutr 79, 899S-906S.

Dangin M, Boirie Y, Garcia-Rodenas C, Gachon P, Fauquant J, Callier P, Ballevre O, & Beaufrere B (2001). The digestion rate of [32] protein is an independent regulating factor of postprandial [33] protein retention. Am J Physiol Endocrinol Metab 280, E340-E348.

Dangin M, Boirie Y, Guillet C, & Beaufrere B (2002). Influence of the [34] protein digestion rate on [35] protein turnover in young and elderly subjects. J Nutr 132, 3228S-3233S.

Farnsworth E, Luscombe ND, Noakes M, Wittert G, Argyiou E, & Clifton PM (2003). Effect of a high-[36] protein , energy-restricted diet on body composition, glycemic control, and lipid concentrations in overweight and obese hyperinsulinemic men and women. Am J Clin Nutr 78, 31-39.

Foster GD, Wyatt HR, Hill JO, McGuckin BG, Brill C, Mohammed BS, Szapary PO, Rader DJ, Edman JS, & Klein S (2003). A randomized trial of a low-carbohydrate diet for obesity. N Engl J Med 348, 2082-2090.

Johnston CS, Tjonn SL, & Swan PD (2004). High-[37] protein , low-fat diets are effective for weight loss and favorably alter biomarkers in healthy adults. J Nutr 134, 586-591.

Layman DK, Boileau RA, Erickson DJ, Painter JE, Shiue H, Sather C, & Christou DD (2003). A reduced ratio of dietary carbohydrate to [38] protein improves body composition and blood lipid profiles during weight loss in adult women. J Nutr 133, 411-417.

Layman DK, Evans E, Baum JI, Seyler J, Erickson DJ, & Boileau RA (2005). Dietary [39] protein and exercise have additive effects on body composition during weight loss in adult women. J Nutr 135, 1903-1910.

McAuley KA, Hopkins CM, Smith KJ, McLay RT, Williams SM, Taylor RW, & Mann JI (2005). Comparison of high-fat and high-[40] protein diets with a high-carbohydrate diet in insulin-resistant obese women. Diabetologia 48, 8-16.

Tessari P, Kiwanuka E, Zanetti M, & Barazzoni R (2003). Postprandial body [41] protein synthesis and amino acid catabolism measured with leucine and phenylalanine-tyrosine tracers. Am J Physiol Endocrinol Metab 284, E1037-E1042.

van Milgen J. (2002). Modeling biochemical aspects of energy metabolism in mammals. J Nutr 132, 3195-3202.

Westerterp-Plantenga MS, Luscombe-Marsh N, Lejeune MP, Diepvens K, Nieuwenhuizen A, Engelen MP, Deutz NE, zzout-Marniche D, Tome D, & Westerterp KR (2006). Dietary protein , metabolism, and body-weight regulation: dose-response effects. Int J Obes (Lond) 30 Suppl 3, S16-S23.