Macro partitioning
Compared with animal protein, plant protein results in lower muscle mass, with a stronger negative effect observed in younger adults (<60 years) than in older adults (≥60 years).
If your goal is maximizing muscle mass, animal protein may offer a slight advantage over plant protein, particularly in younger adults. However, the difference is small, and plant protein is still effective. Focus on getting enough total protein and combining plant sources if possible.
Compared with animal protein, plant protein resulted in lower muscle mass following the intervention (SMD = –0.20; 95% CI: –0.37, –0.03; P = .02), with stronger effects in younger (<60 years; SMD = –0.20; 95% CI: –0.37, –0.03; P = .02) than in older (≥60 years; SMD = –0.05; 95% CI: –0.32, 0.23; P = .74) adults.
Why this rating
Based on a systematic review and meta-analysis of 30 eligible RCTs, though heterogeneity exists.
Source
Effect of Plant Versus Animal Protein on Muscle Mass, Strength, Physical Performance, and Sarcopenia: A Systematic Review and Meta-analysis of Randomized Controlled Trials
Rachel Reid-McCann et al. · Nutrition Reviews · 2025
DOI 10.1093/nutrit/nuae200
More from this paper
- There is no significant difference between plant and animal protein for muscle strength or physical performance.Good
- Animal protein improves muscle mass compared to non-soy plant proteins (rice, chia, oat, potato) and plant-based diets, while soy protein is equivalent to milk protein for muscle mass.Good
Related findings · Macro partitioning
- Total daily protein intake of 1.6 g/kg/day is sufficient for maximizing resistance training-induced muscle gains, with an upper confidence interval of 2.2 g/kg/day.Strong
- Resistance exercise training combined with sufficient dietary protein intake acts synergistically to maximize skeletal muscle hypertrophy, with protein intake saturating around 1.6 g/kg/day for general populations and potentially requiring 2.0-2.2 g/kg/day for resistance-trained individuals.Strong
- Trans fats should be completely eliminated from the diet, as they increase LDL cholesterol, decrease HDL cholesterol, and are directly associated with increased coronary risk.Strong
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