Cycling is so full of overwhelming jargon that sometimes it almost threatens to spoil your fun. If it’s not the complexity of power measurement, it’s the physiology of refueling or the PhD-level physics behind aerodynamics that cheats the wind. The latest buzzword to have us grappling with its meaning is ketones, which some are describing as a revolutionary legal performance-enhancing supplement. More and more WorldTour teams are announcing partnerships with mystery drink providers that are becoming increasingly hard to ignore. But what exactly are ketones and do they really live up to all the hype?
This much is clear: ketones have become ubiquitous among professionals, as I saw for myself in March in Paris-Nice. At several stages, as riders crossed the finish line, they grabbed coats, Haribo and, in some cases, ketones from waiting soigneurs before heading back to their team buses.
Soudal Quick-Step was one of many teams seen drinking and were active on social media during the race, sharing videos of KetoneAid sponsor Remco Evenepoel’s products after the stage. A number of thoughts went through my mind as I witnessed this new phenomenon. Do the riders who use these products really believe in their effectiveness, and on the other hand, those who don’t, condemn them as worthless?
A quick internet search revealed that DeltaG, the ketones used by Mathieu van der Poel’s Alpecin-Deceuninck team, was developed at Oxford University, right next door to where I live. A few emails later and I was on my way to meet the scientists behind the drinks. I wanted to break through the wall of mystery surrounding ketones to find out what all the fuss was about.
Visma-Lease and Bike were the first users of this supplement
(Image credit: Getty Images)
Alternative fuel source
First, what are ketones? In short, they are a fuel produced naturally in the liver when the body breaks down fat and provide an alternative fuel source when glucose availability is limited, such as during long rides. “There is no human body that doesn’t have ketones,” says Professor Kieran Clarke of the University of Oxford, a ketone researcher and the brains behind DeltaG, one of several brands of ketones used in cycling today. “Fat breaks down into ketones,” he explains, “which are very similar to glucose [molecules] and work in a similar manner.”
The ketones used in supplements are ketone esters, a synthetic compound that consists of a ketone group attached to an ester group. In theory, by consuming these exogenous ketones in the form of drinks, athletes are providing themselves with an additional source of fuel in addition to their glucose stores to ensure they can power through a long, strenuous distance. However, the Movement for Credible Cycling (MPCC), which includes Groupama-FDJ, Confidis and Bora-Hansgrohe, among others, bans its member teams from using exogenous ketones. Since ketones are produced naturally, why the skepticism? “The UCI says it is investigating the long-term health effects of ketone use,” MPCC chairman Roger Legeay said. Cycling Weekly. “We want to wait for the results of the investigation.”
Hold your nose: The taste test
In a clip on social media after the recent Flèche Wallonne, Soudal Quick-Step’s Ilan van Wilder was shown holding his nose while sipping a bottle of KetoneAid at the finish line. When I recently tried ketones, I understood why – the taste is horrible.
When I tried ketones to track their effect on my own performance, I was immediately put off by what can only be described as a bitter, metallic taste. The DeltaG product I tried was listed as a blueberry flavor, but it was enough to put you off blueberries for life.
Javier Gonzalez believes bad taste is part of what has raised questions about the legitimacy of ketones. “Bad taste adds to the mystery surrounding ketones. People think, ‘Oh, it tastes awful, it must be doing something really powerful’, so I think that’s probably part of it.
The MPCC’s stance is hardly surprising, especially since the first involvement of ketones in cycling caused so much controversy. This was at the time of the London 2012 Olympics, when it was not yet known whether the substance could violate anti-doping laws. A report in the Mail on Sunday in 2020 revealed that the DeltaG had been covertly tested by some of Great Britain’s top riders in preparation for the Games in a testing program approved by UK Sport. According to Sporting Intelligence, the product was not medically approved at the time, yet 91 guinea pigs from various sports signed non-disclosure agreements stating that if they became ill from using the product, they would not discuss what they were. with those outside the program. The Mail on Sunday report said that if it emerged, the plan was to portray the scheme as GB being simply ahead of the curve in terms of profit margin developments.
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Research on ketones has advanced significantly since then and they are not currently banned by the UCI, the World Anti-Doping Agency (WADA) or the International Olympic Committee. [IOC]. Clarke tells me that exogenous ketones were originally produced at Oxford University at the request of the US Department of Defense. The U.S. military hoped ketones would give soldiers an added advantage, helping them stay fueled longer during low-dose operations behind enemy lines and during combat.
View of Visma
As Martijn Redegeld, Head of Team Nutrition at Visma-Lease and Jonas Vingegaard’s Bike, explains, in cycling ketones are no longer seen primarily as a fuel product, but rather as a recovery aid. “I think the whole buzz around ketones started five or six years ago,” he says.
“There were two different reasons for using them, one was more focused on acute performance benefits, meaning riders had to take ketones shortly before or during a race; another area focused more on recovery purposes and training adaptation responses. I think over the last few years the research has shown the most promising effects in this secondary area, on the recovery side.”
Ketones are said to improve your sleep
(Image credit: Getty Images)
Cycling Weekly contacted other WorldTour teams to discuss the use of ketones but received no response. Some teams have acknowledged their use of ketones but declined to talk about why. Professor Clarke says research reveals that ketones have the power to enhance cognitive performance while providing support on a physical basis. However, Visma’s Redegeld is not yet sure about the cognitive benefits. “That’s one area that research is focusing on, but to be honest, I think that part is still pretty unexplored,” he says. “The evidence is still anecdotal. Clearly, ketones are more than just fuel. At first we thought they were like carbohydrates, just for extra fuel, but now we know they can be thought of as a signaling molecule that triggers all kinds of other processes in the body.”
Overnight Ketones: Sleep Enhancer
(Image credit: Getty Images)
If you can get over the nausea after consuming it, ketones are said to improve your sleep and quickly get you snoozing like a pro. Professor Gonzalez explains why: “They seem to potentially have some effect on the balance of hormones including norepinephrine,” he explains, “which can have a direct effect on sleep, but ketones can also affect sleep indirectly because they also reduce urine production. So if you have a ketone ester, you don’t have to go to the bathroom as much, which can mean you don’t wake up in the night and need to go to the bathroom.”
Researchers at universities around the world continue to investigate the benefits and side effects of ketones. One stumbling block is cost: exogenous ketones are so expensive that it can be difficult to get research projects signed off. “Some of the ketone studies we’re interested in are long-term, we supplement people for weeks, but then the costs skyrocket and it’s difficult to fund,” says Javier Gonzalez, professor of human metabolism at Bath University. “That’s why we don’t currently have any projects on ketones.”
It’s also for reasons of cost that Gonzalez believes amateurs are better off spending their money on other forms of performance enhancement. “I think the cost-benefit ratio [from ketones] it’s small,” he says. “Even if they increase performance, there are probably other, cheaper things that will give you more bang for your buck, at least based on what we currently know.”
For example, the DeltaG ketone drink is available in boxes of three, with the most expensive retail price being £75 per box.
Believers and skeptics alike
Redegeld agrees with Gonzalez about the cost, saying that while amateurs could see benefits from using the product, he would recommend making changes elsewhere first. “My advice is always for amateurs to start with the right basics,” says nutritionist Visma. “Simply meeting your energy needs, getting good calories and the right amount of carbohydrates will do much more good. But I think for the ambitious amateur doing all these things right, ketones can definitely be a plus.”
Like Visma-Lease and Bike, the UAE Emirates – the team of two-time Tour champion Tadej Pogačar – are not part of the MPCC, so they would be free to use ketones. So it is interesting that UAE riders are not advised to use them. Outspoken sports scientist Iñigo San Millán, head of performance for Pogačar’s team, is not convinced. “We know that the best fuel for contracting muscles during high-intensity exercise is glucose, as well as lactate,” says CW. “The ketones are there as extra fuel. Yes, the extra fuel works, but compared to carbs, it’s an inferior, lower quality fuel. This is why when an athlete asks me if they should have carbs or ketones, it’s always carbs. We always try to educate them and explain why using ketones during competition can be harmful.”
Ketones are not banned in the UAE, but San Millán is explaining to riders that there are better alternatives. What about the alleged recovery benefits? “For a recovery drink or formula I will always stick to carbs and protein rather than ketones. In my opinion, ketones are a poor fuel,” says San Millán.
Contrary to university researchers, it is not budget constraints that are discouraging the UAE from using ketones. “Sometimes athletes ask us, ‘Is the team going to supply these ketones?’ The answer is no, and the reason is that we don’t believe they are necessary,” he explains. “In my humble opinion, there are better ways to be nutritionally efficient.”
With highly qualified scientists like San Millán writing off the effectiveness of ketones, it’s hard to understand the faith some teams put in them—especially when they’re unwilling to discuss their rationale. Cycling’s dark past means that any alleged new performance-enhancing substance is bound to attract suspicion. However, amateur riders would have to be very convinced of the benefits of ketones to regularly shell out £75 for a drink offering marginal gains at best.