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SYSTEMATIC REVIEW article

Front. Nutr.

Sec. Sport and Exercise Nutrition

Volume 12 - 2025 | doi: 10.3389/fnut.2025.1663860

This article is part of the Research TopicNutraceuticals in SportsView all articles

Effects of protein supplementation on body composition, physiological adaptations, and performance during endurance training: A systematic review and meta-analysis

Provisionally accepted
Yang  XIAOYang XIAO1ZhengWu  DengZhengWu Deng2Wei  SunWei Sun3JiaYi  LiJiaYi Li1WeiFeng  GaoWeiFeng Gao4*
  • 1Wuhan Sports University Graduate School, Wuhan, China
  • 2Beijing Sport University, Beijing, China
  • 3East China Normal University College of Physical Education and Health, Shanghai, China
  • 4Wuhan Sports University, Wuhan, China

The final, formatted version of the article will be published soon.

This study aimed to evaluate the long-term effects of endurance training combined with protein supplementation on body composition, physiological adaptations (aerobic/anaerobic capacity), and performance. A systematic search was conducted in Web of Science, PubMed, and SPORTDiscus databases on April 16, 2025, using the keywords "endurance training" and "protein supplementation". Meta-analysis was conducted using a random-effects model, and the main effect size of each outcome was summarized using the standard mean difference (SMD), and moderators were explored using subgroup and regression analyses. A total of 23 randomized cross-over trials involving 1146 participants were included. The results showed that protein supplementation during endurance training led to a small, non-significant increase in lean body mass (SMD = 0.13, 95% CI: -0.01, 0.28; p = 0.07) and a significant improvement in time to exhaustion (TTE) during endurance exercise (SMD = 0.45, 95% CI: 0.15, 0.76; p < 0.01). While the overall impact on maximal oxygen uptake (VO2max) was not significant, subgroup analysis revealed that untrained individuals may experience greater improvements in VO2max with protein supplementation (SMD = 0.21). Although aerobic and anaerobic capacities were assessed, protein supplementation did not lead to significant changes in these outcomes, nor did it significantly affect body weight or body fat. In summary, protein supplementation during endurance training appears to modestly enhance endurance performance (TTE) and may offer small benefits for lean body mass, particularly in untrained individuals. However, it does not significantly affect overall body weight, fat mass, or aerobic/anaerobic capacity in the general population.

Keywords: Endurance training, Protein supplements, Nutritional supplements, meta-, Body Composition, aerobic capacity, Athletic Performance

Received: 11 Jul 2025; Accepted: 28 Jul 2025.

Copyright: © 2025 XIAO, Deng, Sun, Li and Gao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: WeiFeng Gao, Wuhan Sports University, Wuhan, China

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