Home Health Athletes swear by ketone drinks. A new study says they don’t...

Athletes swear by ketone drinks. A new study says they don’t work.

Many competitive athletes, especially cyclists and runners, swear by ketone drinks, a popular sports supplement that promises to improve athletic performance by packing many of the purported benefits of a low-carb, high-fat, ketogenic diet into one drink.

You may see riders in the upcoming Tour de France checking out ketone supplementation before going into the race. But in a new study, the supplement did not increase the racing speed of recreational cyclists and instead made them perform worse after ingesting the drink than after a placebo. It also gave gas to many of them.

“In our opinion, there is no evidence that acute intake of ketone supplements during exercise has any benefit for an athlete,” said Chiel Poffé, a postdoctoral fellow at KU Leuven in Belgium, who has studied ketone drinks but was not part of the new study.

But the story of the rise and fall of ketone drinks, if discouraging for athletes, provides the rest of us with a helpful reminder to be wary of nutrition or fitness claims that sound a little too good to be true.

Keto diet in a bottle

It was the high expectations for ketone supplementation that led Martin Gibala, a professor of kinesiology at McMaster University in Canada, and his graduate student Devin McCarthy to undertake the new study, published online in April in the International Journal of Sport Nutrition and Exercise Metabolism. .

With other collaborators, they wanted to test whether the ketone supplement would work in real sports conditions.

The main rationale for athletes ingesting ketones (which come in powdered as well as liquid form) was clear enough. They seemed to be getting a keto diet in a bottle.

On a ketogenic or very low-carbohydrate diet, the body produces ketone bodies, commonly called ketones, which can be used by the heart, brain and other organs as fuel, while the muscles begin to rely mostly on fat and not carbohydrates for energy.

Since our bodies store much more fat than carbohydrates, a ketogenic diet should theoretically allow endurance athletes to train and compete longer and harder before they race or hit a wall.

But any such effect—which has proven elusive in truly elite athletes—requires weeks or months of bacon and butter consumption before a person’s body begins to use fat as its primary fuel.

Drinking your ketones, on the other hand, theoretically seemed to promise a quick and easy way to get the performance benefits of going keto.

Cycle slower on ketones

To see if that promise held true, Gibala and his colleagues recruited 23 trained, adult cyclists who regularly cycled more than five hours a week.

They then had them complete two separate 20-minute time trials on stationary bikes. For one thing, they discounted ketone supplements that are widely available commercially. In contrast, they drank a drink with a similar taste but no ketones.

“It was a very simple study,” McCarthy said.

Some previous ketone studies had required hours of pre-workout fasting or other complex eating habits that serious athletes wouldn’t use during training or competition.

“We wanted to replicate a real-world scenario,” Gibala said, using a time trial format that mimics a short, fast bike race or a 5K or 10K run.

The results were unequivocal. The riders produced about 2 percent less power after drinking the ketone drink than the placebo, which would translate to significantly slower race times.

Their heart rates were also lower after the ketone drink, although they didn’t find the ride any easier, they told the researchers.

The cyclists couldn’t and didn’t ride as hard, in other words, but the effort felt just as depleted as after a placebo.

Burps, bloating and belching

The ketone drink also had other drawbacks. “The taste is terrible, extremely bitter,” said Poffé, who has had the opportunity to sip ketone drinks as part of his research.

The taste was so intensely unpleasant that Gibala and his colleagues had a hard time matching it to a placebo, he said.

The drink also caused gastrointestinal problems for most drivers who complained of bloating, rumbling, flatulence, heartburn and stomach aches. Fortunately, “there were no cases of vomiting or retching from shots,” the study says, although it did occur in some ketone drink trials.

Interestingly, these digestive side effects have been known for some time in sports circles, but the acceptance of the supplement hardly slowed down. “Ketone supplements are still widely used among elite athletes, as far as we know,” said Poffé.

“I suspect some athletes would drink battery acid if someone told them it would improve performance,” Gibala said.

He and his co-authors hope their study will at least give athletes pause before supplementing with ketones before competition. “At this point,” he said, “I think it’s safe to say it’s not likely to help.”

Poffé noted that ketone drinks may still prove beneficial in other athletic contexts. Some research, including from his group’s lab, suggests that ketone supplementation may help with recovery after multiple hard workouts or races.

They may also prove helpful in longer endurance events, such as a five- or six-hour Tour de France stage, said Brendan Egan, an exercise scientist at Dublin City University, who has studied the use of ketone supplements, including mid-10Kers. runners and soccer players. “Studies have mostly been on non-elite athletes in challenges that don’t mimic professional cycling,” he said.

More research is needed, however, before recommendations are made about possible, limited athletic use of ketone supplements, the researchers agreed, and the drinks’ taste and digestive effects are likely to be an unstoppable hangover for many — but not all — competitors.

“They’re pretty bad,” Egan said. But “if an athlete believes they work,” he said, they will endure almost anything.

Got a fitness question? email YourMove@washpost.com and we may answer your question in a future column.

Sign up for the Well+Being newsletter, your source of expert advice and simple tips to help you live well every day

#Athletes #swear #ketone #drinks #study #dont #work