Over the course of 30 minutes, athletes that consumed the ketone drink added an extra 400 meters to their distance traveled.
Normal metabolism turns the food you eat into the energy it needs by the burning of carbs and fat gained from a balanced diet.
Ketosis is a metabolic process that occurs when the body does not have enough glucose for energy and goes into "starvation mode." The body breaks down internal fat stores for energy to make ketones that feed the brain.
The Defense Advanced Research Projects Agency (DARPA), the research branch of the United States Army sent out a $10 million request for the development of an efficient food that soldiers could take onto a battlefield.
The ketone drink was developed for soldiers to generate energy from ketones rather than carbs or fats by biochemist Prof. Kieran Clarke, at the University of Oxford, United Kingdom, and Dr. Richard Veech, at the National Institutes of Health, MD.
The ketone ester drink has previously made it through safety studies, whereby it was proven that the drink has no adverse effects. This new study examines the effectiveness of the ketone supplement and shows it can improve performance for certain activity types.
The drink allowed highly trained endurance athletes to clock up an extra 400 meters distance to their workouts. The supplement works by temporarily switching the primary source of cellular energy from glucose or fat to ketones.
"It's really interesting; with a single drink of nutritional ketone you can do the same exercise with completely different metabolism," says Dr. Pete Cox, a clinician at the University of Oxford and first author on the paper.
"Given the findings of this study, which challenges our fundamental understanding of human physiology, it will be tempting for many to focus on pursuing the endurance and sport-related avenues, but it would be a great shame if the metabolic basis of this work was not further explored," he adds.
Ketone metabolism increased with exercise intensity
"Energy drinks" infused with either carbohydrates, fats, or ketones as a source of fuel were given to 39 cyclists, some of which were former Olympians.
The researchers found that muscles use ketones when provided in the diet, and the amount of ketones used increased in proportion to the intensity of the exercise.
Cyclists that consumed the ketone energy drink presented the lowest lactate levels - a byproduct of glucose utilization by muscle cells - which causes the tired, achy feeling observed after a strenuous workout.
The low lactate levels could account for the reason the cyclists on the ketone drink traveled around 400 meters farther over 30 minutes than the cyclists on the carb and fat drinks.
"The ketone itself is inhibiting glycolysis, so that with the same exercise you're preserving glycogen and producing much less lactic acid - this hasn't been seen before. What may be happening is if you are doing something that isn't a sprint, like going on a 26-mile run, you won't hit the wall as quickly. Not only that, but it stops you from aching afterward."
Prof. Kieran Clarke
Clarke adds that while the ketone drink may assist long-distance athletes, such as marathon runners, it is unlikely to make a significant difference to short-distance athletes, or sprinters, as those are anaerobic workouts and the body needs oxygen to burn ketones.
The supplement will be commercially available within the year, says Clarke. She cautions that the drink should not be consumed in large quantities, because while ketones become the primary metabolite, some glycolysis is also needed for them to have beneficial effects.
While the drink is in development, Clarke and team will continue their investigative work on the biology of ketone metabolism in humans.