Ketone salts are the latest — and supposedly greatest — nutritional supplement for those seeking to improve their fitness and athletic performance. But do they actually work? A study by the University of British Columbia suggests that, in fact, ketone salts may inhibit rather than improve athletic performance during high-intensity exercise.
“Ketone salts are relatively new to the market and there’s not much research on their impact on performance,” says the study’s co-author Jonathan Little, assistant professor in UBC Okanagan’s School of Health and Exercise Sciences. “We know from one previously published study that ketone supplements may improve long-duration endurance performance but we’re interested what happens during short-duration and high-intensity workouts, like running a 10k or cycling up a hill.”
“It turns out that ketone salt supplements actually impair high-intensity exercise performance,” Little said.
Ketone salts work by artificially elevating blood ketone levels, similar to what happens naturally during periods of starvation, and forces the body to rely on burning fat as a fuel, explains Little. Burning fat is a more effective long-term fuel but is more complex to process and isn’t as readily accessible for quick bursts of muscle activity as is a fuel like glucose.
“Elevated blood ketones seem to inhibit the body’s use of glycogen, the stored form of glucose, and favors burning fat instead,” adds Little. “That means that the body’s quick-burning fuel cannot be accessed during high-intensity bursts of activity and athletic performance is dropping off as a result.”
In his study, Little recruited ten healthy adult males with similar athletic abilities and body mass indices. After a period of fasting, they were asked to consume either beta-hydroxybutyrate ketone salts or a flavor-matched placebo, in a randomized order, and then engage in a cycling time trial. Power output on the day participants consumed ketone salts was seven per cent lower than on the day when they consumed the placebo.
Ketone supplements a DARPA idea
The idea of developing ketone supplements came from the Defense Advanced Research Projects Agency (DARPA), the research branch of the United States military, which was looking for the most efficient food for soldiers to take onto a battlefield. One of the people to answer the call was University of Oxford biochemist Professor Kieran Clarke. With Dr. Richard Veech at the National Institutes of Health, she assembled a team who invented the ketone ester drink. A 2016 study found that ketone can improve performance for certain types of activities without any adverse effects.
But Little says the jury is still out, especially when it comes to brief, high-intensity exercise.
“Often these supplements are marketed as a means of improving athletic performance but in this case, the research tells a very different story,” says Little in a press release. “On top of that, the long-term impacts of artificially increasing blood ketone levels — essentially tricking the body into thinking it is in a state of starvation — is completely unknown.”
This is, of c0urse, at odds with the promises being made by ketone salts’ promoters. “Keto Drive is formulated to help support increased blood ketone levels, athletic endurance, mental performance, sustained energy, and fat burn (when combined with exercise!). Get the physical and mental drive you need to power through your day and conquer your workouts,” gushes one ketone manufacturer on Amazon.
“I hope this helps athletes navigate the science of supplements rather than relying on label marketing alone,” Little said.
Since ketones are being sold as supplements, they are unregulated by the Food and Drug Administration. Anyone trying to use supplements to improve their fitness or overall health should consult with their physician first. Don’t rely on advertising, labels, promoters’ claims or news stories.