Originally Posted by
Mrpb
Actually, if you bothered to read that thread you would know that, after debating the issue, Alan modified his position as follows:
Originally Posted by
alan aragon
Note that
I edited out "the current recommendations" from my list since it's too subjective. I instead opted to simply list 1.8 g/kg.
Originally Posted by
alan aragon
If I may push towards a temporary resolution here, is it fair to say that we agree on the following:
1) No controlled comparisons of protein intake have shown significant ergogenic benefit in regards to either muscle gain or retention at intakes greater than 1.8 g/kg.
2) There are studies that have dosed protein above 1.8 g/kg, but have (with debatable/scant exception) used insufficient protein for comparison.
3) Being vehement about an upper limit of 1.8 g/kg is hasty since this dose has not been compared with a higher dose (i.e., in the 2.2-2.7 ballpark) in lean/athletic subjects undergoing resistance training in a deficit.
4) There are inherent limitations with the current literature's expression of protein per unit of gross weight vs per unit of lean mass.
5) Not all training populations or sport situations have received sufficient investigation to warrant vehemence towards 1.8 g/kg as an upper limit of effectiveness.
6) Figures that get spit up in study outcomes are expressed as means (averages). This means that a mixed bag of responses occurred, some substantially higher or lower than the reported mean value. If you really want to rigidly latch on to some mean value and believe that it unquestionably applies to you, then you're making quite the leap of faith.
OP: To learn more about the relevant research, please click here and in summary:
Tarnopolsky et al. (1992) observed no differences in whole body protein synthesis or indexes of lean body mass in strength athletes consuming either 0.64g/lb or 1.10g/lb over a 2 week period. Protein oxidation did increase in the high protein group, indicating a nutrient overload.
Walberg et al. (1988) found that 0.73g/lb was sufficient to maintain positive nitrogen balance in cutting weightlifters over a 7 day time period.
Tarnopolsky et al. (1988) found that only 0.37g/lb was required to maintain positive nitrogen balance in elite bodybuilders (over 5 years of experience, possible previous use of androgens) over a 10 day period. 0.45g/lb was sufficient to maintain lean body mass in bodybuilders over a 2 week period. The authors suggested that 0.55g/lb was sufficient for bodybuilders.
Lemon et al. (1992) found no differences in muscle mass or strength gains in novice bodybuilders consuming either 0.61g/lb or 1.19g/lb over a 4 week period. Based on nitrogen balance data, the authors recommended 0.75g/lb.
Hoffman et al. (2006) found no differences in body composition, strength or resting hormonal concentrations in strength athletes consuming either 0.77g/lb or >0.91g/lb over a 3 month period.
Also see:
Effect of protein intake on strength, body composition and endocrine changes in strength/power athletes. Hoffman JR, Ratamess NA, Kang J, Falvo MJ, Faigenbaum AD. J Int Soc Sports Nutr. 2006 Dec 13;3:12-8.
Macronutrient content of a hypoenergy diet affects nitrogen retention and muscle function in weight lifters. Walberg JL, Leidy MK, Sturgill DJ, Hinkle DE, Ritchey SJ, Sebolt DR. Int J Sports Med. 1988 Aug;9(4):261-6.
Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. Lemon PW, Tarnopolsky MA, MacDougall JD, Atkinson SA. J Appl Physiol. 1992 Aug;73(2):767-75.
Influence of protein intake and training status on nitrogen balance and lean body mass. Tarnopolsky MA, MacDougall JD, Atkinson SA. J Appl Physiol. 1988 Jan;64(1):187-93.
Dietary protein for athletes: From requirements to optimum adaptation. Phillips SM, Van Loon LJ. J Sports Sci. 2011;29 Suppl 1:S29-38.
Protein and amino acid metabolism during and after exercise and the effects of nutrition. Rennie MJ, Tipton KD. Annu Rev Nutr. 2000;20:457-83.
Hartman, J. W., Moore, D. R., & Phillips, S. M. (2006). Resistance training reduces whole-body protein turnover and improves net protein retention in untrained young males. Applied Physiology, Nutrition and Metabolism, 31, 557–564.
Moore, D. R., Del Bel, N. C., Nizi, K. I., Hartman, J. W., Tang, J. E., Armstrong, D. et al. (2007). Resistance training reduces fasted- and fed-state leucine turnover and increases dietary nitrogen retention in previously untrained young men. Journal of Nutrition, 137, 985–991.
Effects of exercise on dietary protein requirements. Lemon PW. Int J Sport Nutr. 1998 Dec;8(4):426-47.
Effects of high-calorie supplements on body composition and muscular strength following resistance training. Rozenek R, Ward P, Long S, Garhammer J. J Sports Med Phys Fitness. 2002 Sep;42(3):340-7.
Increased protein maintains nitrogen balance during exercise-induced energy deficit. Pikosky MA, Smith TJ, Grediagin A, Castaneda-Sceppa C, Byerley L, Glickman EL, Young AJ. Med Sci Sports Exerc. 2008 Mar;40(3):505-12.
Dietary carbohydrate-to-fat ratio: influence on whole-body nitrogen retention, substrate utilization, and hormone response in healthy male subjects. McCargar LJ, Clandinin MT, Belcastro AN, Walker K. Am J Clin Nutr. 1989 Jun;49(6):1169-78.
Macronutrient Intakes as Determinants of Dietary Protein and Amino Acid Adequacy. Millward, DJ. J. Nutr. June 1, 2004 vol. 134 no. 6 1588S-1596S.
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