Energy balance
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.
If you are an athlete, protein supplements may help performance, but likely only because they add calories. If you already meet your energy needs, adding protein powder on top of it may not offer extra performance gains compared to a placebo with the same calories. Focus on total energy intake first.
However, the results indicated that all significant effects were observed in randomized controlled trials where the energy intake between the intervention and control groups was not matched. This suggests that the observed benefits may not be attributable to protein per se.
Why this rating
High-quality Bayesian meta-analysis of 75 RCTs, though the conclusion relies on subgroup analysis of energy matching.
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
- 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
- Whey protein is the only protein source shown to have statistically significant effects on both endurance performance and muscle strength in this meta-analysis.Moderate
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