To optimize muscle protein synthesis, a dose of 20 g of protein per meal is largely sufficient to achieve a significant effect, with the increase to 40 g providing only a marginal gain of approximately 14%.

noli's read

This advice is based on sports physiology studies (RCTs and acute protein synthesis analyses) often cited by Stuart Phillips and his peers. Research confirms that for young, active individuals, a dose of ~20-25 g of high-quality protein triggers a robust anabolic response. The idea that a higher intake (40 g+) might offer additional benefit is nuanced: while the gain in protein synthesis is indeed modest and diminishing after a certain threshold, higher intakes may reduce protein breakdown or be more beneficial in other contexts, such as in older individuals or during less frequent meals. There is therefore nothing exaggerated about the 20 g figure, which remains a solid baseline, but it is important to consider the context (age, lean mass, total requirements). It is not an absolute rule, but an effective distribution strategy for most people.

the sources

No named source held this one up — that absence is part of the verdict.