Lawrence De Plus revealed that he uses ketones and compared the taste of the legal but controversial supplement drink to a gin and tonic.

It was revealed this summer that ketones are widely used by De Plus' team, Jumbo Visma. However, rival teams have expressed concerns about performance gains and possible health effects on the liver.

On Belgian Radio 1's De Tribune, De Plus spoke openly about his and his team's use of ketones.

"If you say you want to use ketones, the team will arrange everything and include it in your supplement plan," de Plus said.

"It tastes a little bit like a gin and tonic, and it captures the imagination. Not everyone on the team uses it, but I think it's good.

"I'm happy with it and glad they don't do it hysterically. Anyone can buy it. It's just a difference in usage."

Ketones are produced in the liver when there are no more carbs to burn and fat stores begin to burn. Synthetic ketones used in conjunction with a low-carbohydrate diet are thought to maintain glycogen stores, reduce lactic acid, and provide an additional energy source to aid recovery. They are classified as dietary supplements, not drugs, and are not on the World Anti-Doping Agency's list of prohibited substances.

According to Kieran Clark, a British scientist who helped develop the ketone supplement, at least six teams used ketones at the 2018 Tour de France, but none wanted to be named. This summer, Jumbo Visma confirmed that it is using ketones along with Lotto Soudal, while ketones have also been linked to the success of Deceuninck-Quickstep.

It has been suggested that Chris Froome and Team Ineos used ketones, but both have explicitly denied it.

"Ketones are nutritional supplements. They can be used in the same way as vitamins. This substance is not on the banned list and other teams are known to use ketones," Jumbo Visma coach Richard Plagge said this summer.

However, many rival team managers have expressed concern and refuse to use them. Some point to the exorbitant cost of the supplements, while others worry about the health implications.

"It occurs naturally when the liver converts lipids (fats) into carbohydrates (sugars)," Jean-Jacques Menouet, team doctor for Arkea Samsic, told AFP. 'I don't want to receive a letter from a player 10 years later saying his liver is ruined.'