The dose that works
The review by Morton et al. (2018, British Journal of Sports Medicine) with more than 1,800 participants found that muscle protein synthesis saturates around 1.62 g/kg of body weight per day for most individuals. Intakes above this threshold do not generate additional muscle under normal conditions.
For endurance athletes: 1.4 to 1.7 g/kg/day
For athletes in a calorie deficit: up to 2.4 g/kg/day (preserves lean mass)
Morton et al., "A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains", BJSM, 2018
The per-meal dose
The leucine threshold for maximum stimulation of muscle protein synthesis sits around 0.24 g of protein per kg of body weight per meal. Around 20 g for an 83 kg athlete; 25 to 40 g for larger or older athletes.
Distribution across the day
Eating protein across 4 to 6 meals throughout the day produces a greater cumulative anabolic response than concentrating the entire intake in 1 to 2 meals. A breakfast with a good protein source (eggs, Greek yogurt, cottage cheese) matters. The classic toast with margarine does not stimulate muscle protein synthesis.
The anabolic window: how much time do I have?
The window is real, but wider than once thought. Schoenfeld (2013) shows that the window of opportunity extends for at least 2 hours after training. The priority of consuming protein immediately post-workout is higher when the athlete trained fasted; if they trained after a meal with protein 1 to 2 h before, the peak of amino acids is still available.
The 1.62 g/kg/day figure is not opinion, it is the statistical breakpoint of the meta-regression by Morton and colleagues (2018), which pooled 49 studies and 1,863 participants. Above this value, the confidence interval still rises up to 2.20 g/kg/day, which is why strength athletes in a gaining phase usually aim for the higher end of the range. Below it, practically nobody saturates the muscle synthesis machinery.
The per-meal math comes from Moore and collaborators (2015): about 0.24 g of protein per kg saturates synthesis in young adults, rising to near 0.40 g/kg in older adults, who respond less to the same stimulus. To trigger it, the official ISSN position stand (Jager et al., 2017) suggests doses with 700 to 3,000 mg of leucine, distributed every 3 to 4 hours throughout the day, which in practice means not concentrating everything at dinner.
The weight of the sport shows up in rugby: the dietary survey by Posthumus and colleagues (2021) with 34 Super Rugby players in New Zealand recorded an average intake of 2.5 g/kg/day among forwards and 2.4 g/kg/day among backs, above the 1.5 to 2.0 g/kg recommendation for contact sports. At the other extreme of pure strength, the Icelander Hafthor Bjornsson pulled 501 kg in the deadlift on May 2, 2020, the first human to surpass half a ton, a mark sustained by years of a strength protocol and elite protein recovery.
The takeaway
The number that matters is not the largest possible, it is the saturation point: 1.62 g/kg/day, according to Morton's meta-regression with nearly 1,900 athletes, which also shows the range rising up to 2.2 g/kg/day in a strength gaining phase. Above that, it is money thrown away. The rest is distribution: 20 to 40 g per meal, 4 to 6 times a day, including breakfast, which usually gets only toast and margarine. Hafthor Bjornsson did not get to the 501 kg deadlift by eating protein at random; he got there with a protocol. The question that remains is not "how much protein can I eat", it is "am I distributing what I already eat in the way the muscle can use". Fix that before buying more supplement.
