The International Society of Sports Nutrition (ISSN) published comprehensive protein intake guidelines based on extensive research by Jäger et al. in the Journal of the International Society of Sports Nutrition (2017). The position stand establishes evidence-based recommendations of 1.4-2.0 grams per kilogram of body weight for individuals engaged in regular training, with adjustments for training intensity and body composition goals.

These recommendations are based on nitrogen balance studies and muscle protein synthesis research demonstrating that protein requirements increase with physical activity. The research shows that higher protein intakes during caloric restriction help preserve lean body mass, while optimal protein distribution across meals supports sustained muscle protein synthesis throughout the day.