- Protein supplements may help increase time to exhaustion during endurance workouts.
- No major changes in body fat, body weight or VO2max were found from protein use.
- The benefits of protein may vary by training level, supplement type and dietary intake.
Protein supplements are a popular choice to help meet protein needs, especially when it’s challenging to get enough in your usual routine. Some research suggests that protein supplementation can improve endurance performance, increase lean muscle mass and enhance recovery. But more studies are needed to understand the best types of protein, timing and distribution for endurance athletes.
To bridge the knowledge gap, researchers aimed to take a deep dive into existing research to understand how combining endurance training with protein supplements impacts the body and performance.
By analyzing data from multiple high-quality studies, they evaluated how this combination affects body composition, fitness improvements (like aerobic and anaerobic capacity) and performance measures such as time trial results and how long athletes can exercise before exhaustion, and the results were published in Frontiers in Nutrition.
How Was This Study Conducted?
To conduct this study, researchers performed a systematic review and meta-analysis, conducting an extensive search of scientific databases. They focused on high-quality, peer-reviewed research, specifically randomized controlled trials, to evaluate the effects of protein supplementation during endurance training. To ensure accuracy, the researchers excluded studies on isolated amino acids, very short interventions or nonhuman research. After gathering all the studies, two researchers carefully reviewed them to ensure they met the criteria, resolving any disagreements with a third researcher.
This evaluation included 23 high-quality studies, all of which were randomized controlled trials, with one being a crossover trial. Of these, 65% were double-blind, while the rest were single-blind or did not report blinding. Most studies included participants from 18 to 63 years old, with only two studies focusing on individuals aged 60 to 65. Participants were categorized as trained or untrained, based on their physical activity levels, and the training programs ranged from endurance-only to combined endurance and resistance training, lasting between six and 26 weeks.
The studies used various types of protein supplements, including whey, soy, milk, casein, collagen peptides, amino acids and beef protein.
What Did The Study Find?
This meta-analysis revealed that protein supplementation had no significant effect on body weight or body fat but showed a small potential benefit for increasing lean body mass. Protein supplementation also did not significantly improve aerobic capacity (VO2max) or anaerobic capacity (peak power).
However, when it came to performance, protein supplementation significantly improved time to exhaustion (TTE), meaning participants could exercise longer before fatigue. Other performance measures, like time trial results and sprint speed, showed no significant improvements. Subgroup and regression analyses explored factors like age, protein intake, and intervention duration but found no significant effects on outcomes like VO2max.
When considering these results, it’s important to understand a few limitations of this study. First, while the researchers only included peer-reviewed and published research to ensure quality, this approach might still introduce some bias, as unpublished studies were not considered. Second, most studies didn’t report how much protein participants were already eating in their typical diets. This made it difficult to determine whether additional protein from supplements provided clear benefits for those doing endurance training. Lastly, the studies varied in how they reported protein supplement dosages, which limited the researcher’s ability to fully assess how the amount of protein consumed might influence the outcomes.
How Does This Apply To Real Life?
For endurance athletes and fitness enthusiasts, this research highlights that while taking protein supplements may not drastically change body weight or fat composition, they may help improve lean muscle mass and extend the time you can exercise before fatigue sets in. This means that if you’re training for a marathon, cycling event or any endurance activity, adding protein supplementation to your diet may help you push through longer sessions and recover more effectively.
However, the study also shows that the benefits might vary depending on factors like your training level, the type of protein you use and how much protein you’re already getting from your regular diet.
The findings also emphasize the importance of tailoring your nutrition to your specific needs. For example, untrained individuals might see more noticeable improvements in aerobic capacity (VO2max) with protein supplementation compared to trained athletes. This suggests that beginners may benefit more from adding protein to their routine as they build their endurance base. But since the research didn’t pinpoint the best protein types or dosages, it’s a good idea to consult with a dietitian or healthcare professional to create a plan that works best for you.
Our Expert Take
A new review and meta-analysis published in Frontiers in Nutrition offers insights into what protein supplementation can do for you. The data suggests that while protein supplements won’t drastically change body weight or fat levels, they may help build lean muscle and boost endurance by letting you push through longer workouts before hitting fatigue. Whether you’re gearing up for a marathon, a cycling race or just trying to level up your endurance game, adding protein via supplementation to your diet could be the key to better recovery and more effective training sessions. That said, the benefits can vary depending on your fitness level, the type of protein you choose and how much protein you’re already getting from your meals.
Since the research didn’t pinpoint the “perfect” type or amount of protein, working with a dietitian or healthcare provider can help you craft a plan that aligns with your goals.
