Why older adults need more protein per meal to build and maintain muscle.
What the evidence says
- “Anabolic resistance”: older adults mount a blunted muscle-protein-synthesis response to a given dose of dietary protein compared with younger adults[1],[2]
- Older men (~71 y) require ~0.40 g/kg body mass per meal to maximize myofibrillar protein synthesis, versus ~0.24 g/kg for younger men (~22 y) — about 67% more protein per meal relative to body weight[1]
- The age difference is postprandial: basal (fasting) MPS rates do not differ between age groups; the gap appears in the response to a meal[1]
- Older adults are less sensitive to low-protein meals, so suboptimal (low-protein) meals cost them more MPS than they cost younger adults[1]
- Roughly 25–30 g of high-quality protein per meal maximally stimulates MPS in both young and older adults, but ”muscle protein synthesis is blunted in elderly when protein and carbohydrate are coingested or when the quantity of protein is less than approximately 20g per meal” (requoted 2026-09-19: large amounts of is not the paper’s)[2]
- Aging does not inevitably blunt the anabolic response when the per-meal protein threshold is met; leucine supplementation may further support the response in older adults[2]
- Practical emphasis for older adults: distribute adequate protein across meals and hit a higher per-meal dose, rather than relying on total intake alone, to preserve muscle and counter sarcopenia[2]
- For older adults, ”new research suggests daily needs” of at least 1.0 g/kg body weight of protein[3]