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.
Beef cattle
On average, cattle will consume 1.4 to 4% of their body weight daily. There are a range of types of feed available for these animals. The standard text in the United States, "Nutrient Requirements of Beef Cattle", has been through eight editions over at least seventy years. The 1996 seventh edition substituted the concept of "metabolizeable protein" for the sixth edition's "crude protein". In the 20th century, Canadian practice followed the American guidance. Already in 1970, the Food and Drug Administration was regulating pharmaceutical supplements in beef cattle feed such as hormones and prophylactic antibiotics.