Dietary supplement
According to US & Canadian Dietary Reference Intake guidelines, the protein Recommended Dietary Allowance (RDA) for adults is based on 0.8 grams protein per kilogram body weight. The recommendation is for sedentary and lightly active people. Scientific reviews can conclude that a high protein diet, when combined with exercise, will increase muscle mass and strength, or conclude the opposite. The International Olympic Committee recommends protein intake targets for both strength and endurance athletes at about 1.2-1.8 g/kg body mass per day. One review proposed a maximum daily protein intake of approximately 25% of energy requirements, i.e., approximately 2.0 to 2.5 g/kg.
Protein efficiency ratio
The U.S. Food and Drug Administration now uses the Protein Digestibility Corrected Amino Acid Score (PDCAAS) as the basis for the percent of the U.S. recommended daily allowance (USRDA) for protein shown on food labels. However, the PER is still used in certain FDA regulations. The US FDA official methods to calculate the PER are as stated in the Official Methods of Analysis of AOAC International, 16th ed. (1995) Section 45.3.05, AOAC Official Method 982.30 Protein Efficiency Ratio Calculation Method; and Official Methods of Analysis of AOAC International, 18th ed. (2005).