Macro partitioning
Whey protein is the only protein source shown to have statistically significant effects on both endurance performance and muscle strength in this meta-analysis.
If you use protein supplements for performance, whey protein is the only source with demonstrated significant benefits for both endurance and strength in this analysis. Other sources (soy, casein, etc.) did not show significant effects.
Only one protein source (whey protein) showed statistically significant effects for both endurance performance [μ(SMD): 0.28, 95% CI: 0.07 to 0.49... ] and muscle strength [μ(SMD): 0.53, 95% CI: 0.01 to 1.05... ]. No statistically significant effects were observed in other types of protein sources.
Why this rating
Based on subgroup analysis; other protein types had non-significant results, but sample sizes for specific types may vary.
Source
The effectiveness of protein supplements on athletic performance and post-exercise recovery − a Bayesian multilevel meta-analysis of randomized controlled trials
Shiao Zhao et al. · Journal of the International Society of Sports Nutrition · 2025
DOI 10.1080/15502783.2025.2605338
More from this paper
- Protein supplementation improves endurance performance and muscle strength compared to placebo, but these benefits are likely attributable to unmatched energy intake rather than protein itself.Good
- An additional daily protein intake of 1 g/kg from supplements, resulting in a total daily intake of approximately 2 g/kg, is most effective for enhancing athletic performance.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
This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →