High-protein diets in trained individuals. 
The United States (US) recommended dietary allowance (RDA) for protein is 0.8 grams per kilogram body weight per day (g/kg/d).  The International Society of Sports Nutrition (ISSN) recently recommended an intake of 1.4-2.0 g/kg/d whereas the United States and Canadian Dietetic Association typically recommend a lower range of 1.2 to 1.7 g/kg/d. It is clear that the US RDA for protein is grossly inadequate for exercising individuals; thus, athletes are typically advised to consume twice the RDA.  This falls within the range commonly recommended by academic societies.  The effect of protein consumption that exceeds these aforementioned guidelines is not entirely known.  This review examines the current literature as it pertains to the influence of very high protein intakes in trained individuals (i.e., humans).  It is the scientific opinion of the author that athletes should consume at least 2.2 g/kg/d of protein.