How much protein, per meal and per day, drives muscle protein synthesis — and why distribution matters at a fixed total.
What the evidence says
- Total daily protein is the foundation for muscle: resistance-training gains in fat-free mass plateau once total intake reaches ~1.62 g/kg/day (95% CI 1.03–2.20), i.e. roughly 0.7–1.0 g/lb[1]
- Protein supplementation during resistance training raised fat-free mass by 0.30 kg and 1-RM strength by 2.49 kg versus control across 49 RCTs (1,863 participants)[1]
- Per-meal threshold: approximately 25–30 g of protein per meal maximally stimulates muscle protein synthesis, in both young and older individuals[2]
- The review reports that ”new research” identifies anabolic and metabolic benefits to consuming ”at least 20–30 g protein at a given meal”[3]
- Muscle protein synthesis responses fall off when a meal provides less than ~20 g protein[2]
- Per-meal ceiling (“muscle-full” effect): a single large protein bolus does not proportionally increase MPS — the response saturates once the per-meal threshold is met, and additional protein is used for other purposes rather than more muscle synthesis[3],[2]
- Distribution matters at equal total: even distribution (~30 g at each of three meals) produced ~25% higher 24-hour MPS than a skewed pattern (~10 g breakfast, ~16 g lunch, ~63 g dinner) at the same ~90 g/day total[4]
- Measured MPS rate: 0.075%/h (even distribution) vs 0.056%/h (skewed toward dinner)[4]
- The typical American pattern of concentrating protein at dinner is suboptimal for 24-hour MPS; moderate protein at each meal is more effective than one large evening dose[4]
- Paddon-Jones and Rasmussen advise: ”Rather than recommending a large, global increase in the recommended dietary allowance (RDA) for protein for all elderly individuals, clinicians should stress the importance of ingesting a sufficient amount of protein with each meal”. That distribution matters more than the daily total is not either paper’s comparison[2]