Overview
- The review published July 31 in Cell Press Blue pooled more than 350 studies across animals and humans and concluded that moderating total protein or restricting certain amino acids links to better metabolic markers and slower biological ageing.
- Researchers identify raised fibroblast growth factor 21 (FGF21) and reduced activation of growth pathways such as mTOR/IGF‑1 as key mechanisms that can raise energy use, improve blood sugar control, and reduce inflammation.
- Evidence is strongest in animals and short-term human trials, so authors say larger, longer randomized human studies are needed before broad diet recommendations are issued.
- Benefits are not universal: relatively sedentary adults appear most likely to gain from moderate protein cuts while athletes, many older adults, pregnant and breastfeeding people, and those recovering from illness often need higher protein to preserve muscle and function.
- The review challenges the booming high‑protein consumer trend and may reshape guidance and product marketing, but it stresses moderation rather than deficiency and calls for personalized advice tied to age, activity and health status.