REF-580 · Schoenfeld & Aragon, 2018 · Journal of the International Society of Sports Nutrition, · Paper · PubMed
Per-meal anabolic target ~0.4 g/kg → distribute across ≥4 meals to reach ~1.6 g/kg/day
Key Findings
The old ceiling: MPS in young adults is said to be maximised at ~20–25 g of high-quality protein per meal, with excess oxidised or converted to urea — but that evidence is specific to fast-digesting proteins given alone; slower proteins and mixed meals delay absorption and conceivably raise utilisation.
The data indicate that higher doses (>20 g) do increase amino-acid oxidation, but not all the extra amino acids are lost — some are used for tissue building.
Authors' conclusion: to maximise anabolism, target 0.4 g/kg per meal across a minimum of four meals to reach a minimum of 1.6 g/kg/day; at the upper daily intake reported in the literature (2.2 g/kg/day) the same four meals would need a maximum of 0.55 g/kg per meal.
Practical Application
Narrative review (2018): the "20–25 g per meal ceiling" comes from fast proteins eaten alone; the authors' guideline is 0.4 g/kg per meal over at least four meals (≥1.6 g/kg/day), up to 0.55 g/kg per meal when the day totals 2.2 g/kg.
Default day for a muscle-building/masters athlete: 4 meals, each ~0.4 g/kg → ~1.6 g/kg/day, convergent with the Morton break point (REF-579).
Limitations
Narrative review; 0.4 g/kg/meal is a pragmatic upper estimate; the ≥4-meal recommendation is the authors' inference, not an RCT-tested schedule.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from C: narrative review without systematic method (rubric: C+)
Content correction 2026-09-27
Level C -> C+ per rubric (narrative review). Added the abstract's own numbers (20–25 g, >20 g oxidation, 2.2 g/kg/day → 0.55 g/kg/meal); pre-sleep casein advice labelled as not from this paper; lead rewritten to the review's conclusion; cross-references given refIds.