Jäger et al. 2017, ISSN position stand: protein and exercise

The International Society of Sports Nutrition position stand on protein and exercise recommends 1.4–2.0 g/kg/day total protein for exercising individuals, with individual servings of approximately 0.25 g/kg body weight (20–40 g in absolute terms) to maximise the muscle protein synthesis response; doses should be distributed evenly every three to four hours across the day. For endurance athletes specifically, the stand advises approximately 0.25 g of protein per kg body weight per hour of endurance exercise to reduce muscle damage markers. Strong evidence.