New research says the body can use more than 30g protein per meal

A 100g protein dose did not just get absorbed, it kept driving muscle protein synthesis and whole-body protein balance for more than 12 hours. That is the piece of evidence that knocks the old 30g-per-meal shortcut off its pedestal, and it matters because absorption is not the same thing as an anabolic response.

The 2023 Cell Reports Medicine study from Jorn Trommelen, Andrew M. Holwerda, Luc J.C. van Loon and colleagues at Maastricht University in Maastricht, Netherlands, used a quadruple isotope tracer feeding-infusion approach to compare 100g of protein with 25g after intense whole-body resistance exercise. The larger dose produced a greater and more prolonged response, with dose-dependent increases in dietary-protein-derived amino acid availability, muscle protein synthesis and whole-body net protein balance. The Maastricht group later said the anabolic response to protein ingestion had no apparent upper limit in magnitude and duration in vivo in humans.

That finding matters because the old ceiling was built on a narrower kind of evidence. For years, fitness advice leaned on short-term single-meal studies using fast-digesting whey protein and brief measurements of muscle protein synthesis, often after resistance exercise. Those studies were useful, but they also encouraged a false takeaway: that anything above roughly 20g to 30g per meal was wasted. The newer data do not support that oversimplification. They suggest a bigger meal can keep amino acids available for much longer, and that the body can keep using them long after the first post-meal spike has passed.

The practical consequences are different for different people. For athletes, the question is no longer whether a larger recovery meal can count, but how much protein over the day supports training adaptation. For older adults, who often need a stronger anabolic stimulus to protect lean mass, the finding pushes against rigid fear of “too much” protein at one sitting. For everyday eaters, it makes meal planning less mechanical: one large protein meal is not automatically inferior to a perfectly spaced day of smaller servings.

That does not mean the old distribution advice is useless. Current International Society of Sports Nutrition guidance still points to roughly 0.25g per kilogram of body weight, or about 20g to 40g of high-quality protein per meal, with 700mg to 3000mg of leucine and spacing every 3 to 4 hours. But the new analysis changes the frame. The body is not capped at 30g, and protein planning should stop treating every meal as if it hits a hard biological limit.