Protein dose-response for lean body mass Original paper

To gain or preserve muscle, you need to eat enough protein, but what constitutes “enough” varies between people, based notably on muscle mass, fat mass, total caloric intake, and activity level.

A recent meta-analysis investigated the dose-response relationship between protein intake and muscle mass.^[1] However, the participants of the included studies were all engaged in resistance training, whereas the present meta-analysis was designed to include other populations as well.

This systematic review and meta-analysis included 105 papers (5,402 participants) that looked at the effect on skeletal muscle of different levels of protein intake.

Increasing protein intake by as little as 0.1 gram per kilogram of body weight per day (0.1 g/kg/day) can increase muscle mass. Protein intakes between 0.5 and 3.5 g/kg/day were associated with increased muscle mass regardless of weight training. The dose-response relationship diminishes rapidly at doses higher than 1.3 g/kg/day, but resistance training attenuates this reduction, such that total protein intakes as high as 3 g/kg/day may still be beneficial.

Not only does dietary protein provide building blocks for the muscles, but it also serves as a signal for the body to build muscle. Postprandial blood levels of the amino acid leucine, notably, are highly correlated with muscle protein synthesis (MPS).^[2]