If you’ve been watching the Tour de France, you’ve probably heard of ketones. They’re the drinkable nutritional supplement that are believed to give a boost of performance. So it should come as no surprise that World Tour cycling teams are using them to aid the performance of their riders. According to some reports, as many as six teams currently racing the Tour de France could be using ketones.
So how do these ketones affect runners, and should runners consider trying them?
Ketones are produced naturally when the liver breaks down fatty acids instead of the glucose from carbohydrate for fuel. It happens when the body is deprived of carbohydrate and glycogen stores are depleted, and must burn fat as fuel instead. This is called ketosis. Ketosis may happen naturally after prolonged exertion (such as a long training run), when the body’s glycogen stores are depleted. Ketosis can also be achieved through limiting carbohydrates in the diet. These exogenous ketone supplements help the body achieve a state of ketosis without modifying your diet.
Ketosis is suggested to be beneficial for endurance exercise because it can train the body to use fat over carbohydrates as a source of fuel. Because the body can store much greater quantities of fat than it can of carbohydrate, if you train your body to burn fat instead of carbs, you should be able to run longer without needing to refuel.
Canadian dietitian and sports nutritionist Jennifer Sygo says, “Exogenous (orally consumed) ketones may have a role to play in either endurance performance or recovery, but this is based on very preliminary research. The type of ketone supplement matters a lot, and they are insanely expensive, ranging from $30-$90 per dose. So, for most runners, this isn’t within their reach, or even worth the possibly small benefit they could provide.”
The most popular supplement (and the one primarily used by Tour riders) is made by a company called HVMN. A one-time order of three bottles of Ketone Ester costs $99 USD, a pretty penny for only three doses of the supplement.
But studies on ketones are in their infancy and many specialists, including Sygo and Team Sunweb (professional German cycling team) doctor Anko Boelens, aren’t sold on the product or its benefits. Boelens says, “There is much uncertainty about the efficacy. There are even studies that show that it has a negative effect on sports performance. That the remedy would only be good for recovery. We want to be sure that we will not harm our riders.”
As of now, ketones are not on the WADA prohibited list.