Jumbo-Visma Scrutinized For Use Of Ketones

The Tour de France is again embroiled in a debate over what cyclists put in their bodies after Dutch team Jumbo acknowledged they were using a dietary aid believed to boost stamina.

The team responded to questions from Dutch newspaper De Telegraaf by saying they were using drinks based on a substance called ketones, which occur naturally in the body.

Jumbo team manager Richard Plugge says the use of ketones is nothing unusual and is widespread among Tour de France riders.

"It's a food supplement, like vitamins," he told De Telegraaf.

Ketones are "supplementary fuel for the muscles," said Jean-Jacques Menuet, the doctor for a rival team, Arkea-Samsic.

Jumbo won four of the first 11 stages on this year's Tour de France.

Mike Teunissen won the opening stage before Jumbo romped to victory in the team time trial the next day. Dylan Groenewegen won stage six in a sprint and Wout Van Aert took stage 10 on Monday.

On the Tour's rest day on Tuesday, Ineos team principal Dave Brailsford described Jumbo as "the most improved team over the past three years."

Brailsford, who has masterminded six Tour de France wins, said Jumbo had an "open-minded and expansive approach."

Ketones are produced by the liver during intense dieting, but a laboratory version is now cheaply and easily available.

Ketones are classified as a food supplement rather than a drug and are not on the World Anti-Doping Agency's list of doping products.

Two of three WADA criteria would have to be met before they are added -- namely, if it enhances, or potentially enhances, performance, if it violates the spirit of sport or if it is an actual or potential health risk.

For the moment, ketones do not appear to be harmful.

"They naturally occur when the liver turns lipids (fats) into glucid (sugar)," Menuet, the Arkea-Samsic team doctor, told AFP, adding that this would happen during an extreme diet.

Artificial ketones, first created in laboratory conditions in the English city of Oxford, have the same effect.

"At first it cost thousands of euros for one bottle, but now you can get a bottle on the internet for between 30 euros and 90 euros," Menuet said.

Simon Verdonck, team doctor at the French team Cofidis, told AFP that ketones work by extending the amount of time before the body starts using its stored sugars as fuel.

"When you go full gas, your body uses glucids rather than lipids," said Verdonck.

"Ketones delays the use of glucids, saving them for the end of a stage."

Verdonck says he first heard of ketones five years ago but "the effects remain mysterious over the long term" and, until tests have been done on potential negative effects, Cofidis will not be using them.

Menuet agrees.

"I don't want to receive a letter in 10 years from a rider telling me that his liver is ruined," he says.

Vincent Lavenu, of the AG2R team, has called for the use of ketones to be halted immediately.

"For equality in this sport we need a swift reaction," he said.

South America Could Sweep Grand Tours With Vuelta Win

A swathe of absentees leaves the door open for a first-time winner and a South American clean sweep of Grand Tour victories this season as the Vuelta a Espana begins on Saturday.

Report: Doping Threatens Colombia's Cycling Talent Production Line

Colombian cycling reached its zenith last month when pint-sized climber Egan Bernal became his country's first winner of the sport's greatest race, the Tour de France.

FloBikes To Broadcast Vuelta a España And World Championships In Canada

Join Pro now to watch the 2019 Vuelta a España live and on-demand.

Carapaz In Doubt For Vuelta Following Training Crash

Ecuador's Richard Carapaz, winner of this year's Giro d'Italia, has injured his shoulder and could miss the start of the Vuelta a Espana on Saturday.

Jakob Fuglsang To Ride 2019 Vuelta, Re-signs With Astana

Danish veteran Jakob Fuglsang penned a new two-year deal with Astana on Wednesday in a timely boost ahead of the Vuelta a Espana which gets underway this weekend.

The Best Climbers At The Vuelta a España

The Vuelta a España is known as the grand tour for pure climbers. This year’s Vuelta lives up to that reputation and then some. With 57 categorized climbs and eight summit finishes in the 2019 Vuelta, there will be no shortage of battles amongst the peloton’s top climbers throughout the three weeks of racing. 

The Top Sprinters At The 2019 Vuelta a España


The Vuelta a España is known as a race for the pure climbers, however the 2019 edition has included many opportunities for sprinting talent. There are six flat days for the sprinters in this year’s Vuelta, three of which come in the final week. 

Five Unheralded Riders That Could Win La Vuelta

Vuelta Favorites And Underdogs

The Vuelta a España is in many ways the proving ground for riders in the peloton in need of grand tour experience. The courses are as challenging (if not more so) than the other two grand tours, but with many of the marquee GC riders recovering after the Tour de France, the Vuelta stands as an opportunity for hidden talent.

Five Big Favorites For The 2019 Vuelta a España

Vuelta Favorites And Underdogs

For some, the Vuelta a España is a chance for redemption at the end of a trying season. For others, the Vuelta stands as an opportunity to make a first mark on grand tour racing. In 2019 the Vuelta has a line up of bonafide grand tour stars who have something yet to prove this year. 

Roubaix Winner Gilbert To Return To Lotto-Soudal

Philippe Gilbert, the 2012 road-race world champion, will return to Lotto Soudal next season at the age of 38 on a three-year contract, the team announced on Monday.