Macro partitioning
Increasing protein intake to ≥1.6 g/kg/day significantly improves lower-body strength gains in healthy adults undergoing resistance exercise, but has no significant effect on handgrip strength or physical functional performance tests.
If your goal is to increase raw strength (like your squat or leg press numbers), ensure you are eating at least 1.6g of protein per kg of body weight while lifting. However, do not expect this extra protein to directly improve your balance, agility, or daily functional tasks like stair climbing; those require specific functional training.
Lower-body strength gain was slightly higher by additional protein ingestion at ≥1.6 g of protein/kg/day during RE training (SMD = 0.40, 95% CI 0.09:0.35, P < 0.01, 19 studies, low level of evidence). The effects of ingesting more protein are unclear when assessing handgrip strength and only marginal for performance in physical function tests.
Why this rating
Based on 19-32 RCTs but rated 'low' or 'very low' certainty of evidence due to heterogeneity and study design limitations.
Source
Systematic review and meta‐analysis of protein intake to support muscle mass and function in healthy adults
Everson Araújo Nunes et al. · Journal of Cachexia Sarcopenia and Muscle · 2022
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