The “your body can only absorb 30g of protein” claim is wrong. But it’s wrong in an interesting way.

One of the most persistent myths in nutrition is that the body can only “absorb” or “use” 30 grams of protein per meal. Schoenfeld and Aragon (2018) addressed this directly in the Journal of the International Society of Sports Nutrition and concluded that the claim is not supported by the evidence.

The confusion stems from conflating two different concepts: absorption and MPS stimulation.

Nearly all ingested protein is absorbed — the intestine is remarkably efficient at extracting amino acids from food. Even at very high intakes, only a small fraction passes through undigested. So the “30g limit” on absorption is simply wrong.

What does have a per-meal ceiling is the rate of muscle protein synthesis. As discussed in our article on the muscle full effect, Moore et al. (2009) showed that MPS is maximally stimulated by approximately 20g of high-quality protein (~10g EAAs) in young adults after exercise. Protein beyond that amount is absorbed and used — just not for additional muscle building. It’s oxidized for energy, used for other body protein synthesis, or converted to urea.

Trommelen et al. (2023) published an important update in Cell Reports Medicine showing that larger protein doses (100g) did result in greater total amino acid utilization over 12 hours — but the rate of MPS was not higher at any given time point. The body processes it all eventually, just not for muscle building all at once.

The practical takeaway: eating more than 30g of protein per meal isn’t wasted, but splitting protein into 3–4 meals of 25–40g (plus EAA supplements between meals) produces more total daily MPS than fewer, larger protein meals.

References

1. Schoenfeld BJ, Aragon AA. How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. J Int Soc Sports Nutr. 2018;15:10. PubMed
2. Moore DR, Robinson MJ, Fry JL, et al. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr. 2009;89(1):161-168. PubMed
3. Trommelen J, van Lieshout GAA, Nyakayiru J, et al. The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans. Cell Rep Med. 2023;4(12):101324. PubMed