Protein for Endurance Training: What the Latest Research Tells Us

Is protein just for lifters? Not quite. A new systematic review and meta-analysis published in Frontiers in Nutrition is challenging that assumption. By analysing 23 trials involving 1,146 participants, researchers investigated the effects of protein for endurance training, looking at how it influences performance, recovery, and body composition over time.

Here’s what anyone training for endurance should know.

Time-to-Exhaustion Gets a Boost

The standout finding: supplementing with protein during an endurance training programme significantly improves time-to-exhaustion. In other words, people were able to go for longer before fatigue set in. This is a key performance marker in endurance activities like running, cycling, and rowing.

Protein is often associated with building muscle, but this study highlights its lesser-known role in supporting sustained performance.

Lean Mass: A Modest but Meaningful Gain

The analysis also revealed a small, though statistically non-significant, increase in lean body mass. While not dramatic, this gain could still be meaningful for those looking to maintain or build muscle during high-volume endurance training.

Interestingly, untrained individuals experienced more noticeable changes in lean mass. This suggests that training status plays a role in how the body responds to added protein.

No Major Impact on VO₂max or Body Fat

Despite the endurance benefits, protein supplementation showed minimal effect on VO₂max, aerobic or anaerobic capacity, body weight, or fat mass. However, the review noted that less experienced individuals may experience greater physiological changes. This is particularly useful for beginners or those just starting an endurance routine.

Recovery Still Matters

Even in areas where performance metrics didn’t shift significantly, protein still plays a key role in recovery. Consuming protein post-exercise helps replenish glycogen stores and supports muscle repair. This is essential for anyone doing multi-day training or back-to-back sessions.

For best results, pair protein with carbohydrates after training to accelerate recovery and reduce muscle breakdown.

Final Thoughts

This meta-analysis adds valuable insight into the role of protein for endurance training. While it may not dramatically change VO₂max or body fat, it can help improve endurance capacity and support recovery – both critical for consistent progress.

As always, quality matters. Choosing a clean, complete, and sustainably sourced protein makes a difference, especially for those training hard and living consciously.