Protein Thresholds Limit Muscle Gains

Randomized‑trial evidence suggests that adding protein helps muscle growth only up to a point: across resistance‑training studies extra protein produced no further fat‑free mass gains once daily intake was roughly 1.6 g per kg body weight. Older adults also show ‘anabolic resistance’, so their needs and the value of supplements depend on appetite, baseline intake, and whether they actually train. — This reframes many consumer and policy conversations about protein and supplements from 'more is better' to ‘contextual thresholds’, affecting spending on supplements, dietary guidance for ageing populations, and healthcare prevention strategies.