Ketones: The Performance Fuel Elite Athletes Are Banking On
By Seiji Ishii
Editor in Chief
How cycling’s most controversial supplement is reshaping endurance performance and what the science really shows.
When nine out of 10 cycling teams competing in the Tour de France are using ketone drinks¹, the cycling world takes notice.
Team Visma-Lease a Bike and other top WorldTour teams continue to utilize ketones to aid their athletes’ recovery and enhance performance, with team managers openly discussing their use.
But what exactly are these ketones that have become cycling’s worst-kept secret? And more importantly—do they actually work?
What Are Ketones in an Athletic Context?
Ketones are simple compounds made of hydrogen, carbon, and oxygen. When your body primarily uses ketones for energy, this is known as ketosis². Your liver makes these naturally when you’re not getting enough carbs, basically serving as a backup fuel source.
For athletes, ketones can alter how the body utilizes fuel by reducing glucose (sugar) use in muscles, limiting fat breakdown, and protecting muscles from breaking down during exercise³.
Think of ketones as your body’s backup power system—but one that elite athletes are now trying to access without the typical requirements of fasting or strict low-carb diets.
The Performance Promise
The most compelling research comes from the work of Belgian sports scientist Professor Peter Hespel with professional cycling teams.
By the third week of training, the group that took ketones was able to handle 15% more training load than the control group and push 15% higher power output in time trials⁴.
The 2016 study by Cox and colleagues, a notable study, sparked the popularity of ketone supplements with a significant increase in distance covered during 30 minutes of cycling in trained athletes⁵. This groundbreaking research showed that ketones, when combined with carbs, could provide a competitive edge for endurance athletes.
Research continues to explore the potential benefits, with studies investigating how ketones might optimize energy use during different types of exercise and training phases⁶.
Where Ketones Shine: Recovery
The strongest evidence for ketones lies in recovery—which is crucial for multi-day events like the Tour de France.
“Recovery is arguably where ketones deliver their greatest gains,” says Hespel. “Our subjects did intense exercise to empty their energy stores and then took a ketone drink during recovery. We showed that muscle repair and building rates were higher⁷.”
After 3 to 4 hours of racing, refueling energy stores is essential for muscle repair (when the body fixes and builds new muscle after exercise), allowing cyclists to be ready for the next day of racing⁸.
One unexpected benefit is the ketones’ effect on appetite. Pro cyclists often become fatigued from the constant need to consume massive amounts of calories during multi-stage races, making it challenging to maintain proper nutrition throughout events like the Tour de France.
Poor nutrition can impact sleep, recovery, and energy levels the next day. Ketones don’t seem to affect appetite, and so they can help speed up recovery⁹.
The Fuel Switching Science
One sign that our body is burning carbs during exercise is an increase in blood lactate levels. Ketone drinks consistently lower lactate levels during exercise, which typically means less carbohydrate burning and potentially more efficient energy use¹⁰.
This carb-sparing effect could be particularly beneficial during longer endurance events where preserving glycogen stores becomes crucial for maintaining performance throughout the competition.
Brain Benefits: The Mental Edge
Ketones show promising effects on mental function during exercise. Ketone supplements helped maintain cognitive performance during repeated high-intensity exercise in soccer players, suggesting that ketones may help preserve mental sharpness under physical stress¹¹.
The brain connection makes sense: ketones provide 27% more energy than glucose and are a significant energy source for the brain¹². This could mean better decision-making and mental toughness during competition, which can be the difference between winning and losing in elite sports.
Ketones: Real World Use Challenges
Despite the scientific interest, practical use has traditionally faced some hurdles:
Cost Factor: Traditional ketone salts cost $36 to $50 for just a few servings, while ketone esters can cost $30 to $35 per serving. However, The Feed offers more accessible ketone options that deliver the benefits at a better price point for everyday athletes.
Taste Considerations: Early ketone ester drinks had a distinctive bitter taste that many athletes found challenging. The ketone products available on The Feed have been formulated with improved taste profiles, making them much more palatable for regular use during training and competition.
Dosing Optimization: Most positive research used ketone ester products, and scientists continue to refine the best protocols. The Feed’s ketone selection includes products with research-backed dosing that takes the guesswork out of supplementation, allowing athletes to benefit from proven protocols¹³.
Professional Cycling’s Growing Adoption
The cycling world is increasingly embracing ketones. High-profile athletes, such as retired sprinter Mark Cavendish and current champion Remco Evenepoel, are advocates for their use¹⁴.
There’s a clear trend—backed by a 2024 review—toward using ketones primarily for recovery benefits, suggesting the focus has shifted from direct performance boost to recovery optimization and training adaptation¹⁵.
Rule-makers are supportive: The World Anti-Doping Agency (WADA) does not prohibit ketone supplements, allowing athletes to use them legally in all competitive sports, including professional cycling.
Post-Exercise: The New Frontier
The most exciting developments focus on taking ketones after exercise. Increasingly, studies demonstrate the beneficial effects of taking ketones after workouts. The real potential of ketone supplements may be in boosting post-exercise recovery and training improvements¹⁶.
Recent studies found that post-exercise ketone supplements reduce overtraining symptoms and improve sleep, muscle-building signals, red blood cell production hormones, and blood vessel growth in muscles¹⁷. This suggests that ketones could be particularly valuable for athletes during heavy training phases or competition seasons.
The Verdict: Promising Performance Tool
Studies suggest that ketone supplements have beneficial effects on endurance performance, recovery, and preventing overtraining. Research continues to uncover new applications and optimal protocols for different athletic scenarios¹⁸.
For both elite and recreational athletes, ketones may offer gains in recovery and mental performance. The growing adoption among professional cycling teams suggests real-world benefits that extend beyond laboratory settings.
Ketones represent an advanced tool that works best when fundamental nutrition, hydration, and recovery practices are already optimized.
The story of ketones in sports continues to evolve positively. They represent an exciting advancement in precision sports nutrition—where targeted interventions can provide competitive advantages and support athletic development.
Want to explore ketone supplements? Start with proven basics first: optimize your carb fueling, hydration strategy, and recovery habits. When these fundamentals are mastered, ketones could be a valuable addition to your performance toolkit.
Always consult with qualified sports nutritionists and medical professionals before making significant changes to your supplement routine.
References
Llosa, F. Interview with NutraIngredients-USA. KetoneAid, 2023.
Stubbs, B.J., et al. “On the Metabolism of Exogenous Ketones in Humans.” Frontiers in Physiology, vol. 8, 2017.
Pinckaers, P.J.M., et al. “Exogenous Ketone Supplements in Athletic Contexts: Past, Present, and Future.” International Journal of Sport Nutrition and Exercise Metabolism, vol. 32, no. 6, 2022, pp. 424-447.
Canadian Cycling Magazine. “What are ketones and why are the Tour de France’s top teams using them?” July 17, 2019.
Cox, P.J., et al. “Nutritional ketosis alters fuel preference and thereby endurance performance in athletes.” Cell Metabolism, vol. 24, no. 2, 2016, pp. 256-268.
Evans, M., et al. “Metabolism of ketone bodies during exercise and training: physiological basis for exogenous supplementation.” Journal of Physiology, vol. 595, no. 9, 2017, pp. 2857-2871.
Cyclist Magazine. “Ketones for cycling: What are they, do they work, and are they banned?” January 31, 2024.
Sports Pharmacy Network. “The Future of Performance Nutrition in the Tour de France: Ketones and Sodium Bicarbonate.” August 2, 2024.
Ibid.
Precision Fuel & Hydration. “Ketones: A game-changer for endurance athletes?” December 5, 2022.
Quinones, M.D., et al. “Ketone Ester Supplementation Improves Some Aspects of Cognitive Function during a Simulated Soccer Match after Induced Mental Fatigue.” Nutrients, vol. 14, no. 20, 2022.
University of Connecticut. “UConn to Participate in First Ever Clinical Trial of Ketogenic Supplements and Healthy Aging.” UConn Today, October 11, 2023.
NutraIngredients-USA. “The rise of exogenous ketones for athletic recovery.” February 22, 2024.
NutraIngredients-USA. “Where is the ketones market for sports nutrition heading in 2025?” January 30, 2025.
Ibid.
Robberechts, R., et al. “Defining ketone supplementation: the evolving evidence for postexercise ketone supplementation to improve recovery and adaptation to exercise.” American Journal of Physiology-Cell Physiology, vol. 326, no. 1, 2024, pp. C143-C160.
Ibid.
Valenzuela, P.L., et al. “Perspective: Ketone Supplementation in Sports—Does It Work?” Frontiers in Physiology, vol. 11, 2020.