Ketone salts are a dietary supplement that “encourage” the body to derive its energy by burning fats. This supplement is meant to promote weight loss, and some say that it might boost athletic performance. But is that true?

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Don’t always trust the label; ketone salt supplements may do more harm than good when it comes to athletic performance.

You may have heard of the ketogenic, or “keto,” diet, which is based on fat- and protein-loaded foods and intented to eliminate carbohydrates as much as possible.

The keto diet works by causing ketosis, which is a process that relies on burning fat to derive energy, rather than taking the calories from carbohydrates.

Ketone salts are meant to increase the level of ketones in the blood, similarly to ketosis, so that the body will derive its energy from them. Numerous online resources suggest that this nutritional supplement can be used as an aid to weight loss, as well as acting as a reliable energy booster for athletes.

Researchers from the University of British Columbia’s Okanagan Campus in Kelowna, Canada, set out to test whether or not ketone salts could actually improve athletic performance.

As study co-author Prof. Jonathan Little notes, “We know from one previously published study that ketone supplements may improve long-duration endurance performance, but we’re interested [in] what happens during short-duration and high-intensity workouts, like running a 10 kilometers or cycling up a hill.”

The study’s findings were recently published in the journal Applied Physiology, Nutrition, and Metabolism.

The researchers explain that, while burning fat may be a reliable long-term energy resource, this is a long and complex process. What this means is that energy derived from fat may not be ideal for athletic pursuits, which usually tap into “quick” sources of energy such as blood glucose.

Elevated blood ketones seem to inhibit the body’s use of glycogen, the stored form of glucose, and favors burning fat instead. That means that the body’s quick-burning fuel cannot be accessed during high-intensity bursts of activity.”

Prof. Jonathan Little

This, he says, causes “athletic performance [to drop] off as a result.”

For the purpose of the new study, the researchers worked with 10 adult men matched for athletic performance and body mass index (BMI).

Following a period of fasting, the participants were given either beta-hydroxybutyrate ketone salts or a placebo on a random basis. Half an hour after having ingested either the supplement or the placebo, they engaged in a timed cycling trial.

The team found that compared with the day that they took the placebo, when taking the ketone salts, the participants’ performance — in terms of power output — was 7 percent lower.

“It turns out that ketone salt supplements actually impair high-intensity exercise performance,” says Prof. Little.

Prof. Little emphasizes that the study’s findings do not support the notion that ketone salts should be used by athletes who want to boost their performance. In fact, the experiments so far seem to indicate the contrary.

He says, “Often these supplements are marketed as a means of improving athletic performance but in this case, the research tells a very different story.”

He also notes that ketone salt supplements may have other adverse effects that as yet remain unknown, and this is a further reason for caution.

“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,” warns Prof. Little.

He explains that the study’s findings should help athletes to gain a better understanding and awareness of the pros and cons of such supplements, which may be misguidingly advertised.

“I hope this helps athletes navigate the science of supplements rather than relying on label marketing alone,” he concludes.