Alejandro Valverde says he’s the thinnest he’s ever been ahead of the Tour de France

Alejandro Valverde says he is currently at the lightest weight he's ever been ahead of the Tour de France.

The world champion returned to racing after injury at the Route d'Occitanie stage race in France in June looking noticeably thinner than he had done during the earlier part of the year.

In an interview with Marca, the 39-year-old says he wanted to see how his body would respond to further weight loss during the four-day race, and says he is still "very thin" as he prepares for the Tour de France on Saturday in Brussels. The Spanish website says Valverde weighed in at 58.6kg (his approximate height is 1.77m).

"It is true that I have never been at this weight, I am very thin," Valverde said.

"It was something I set out to do, stay so thin to see how my body stayed. I also didn't want to lose too much because then you run the risk of losing muscle and strength, which is not the idea. But in Occitanie I saw that the body responded well for four days, the results were good."

Valverde added that he has already added a kilo in weight since Occitanie, in which time he's taken victory in the road race at the Spanish National Championships. However, he says managing weight will be different under the three-week stresses of the Tour.

"What happens is that now the Tour is not four days, but 21. It's a really demanding race. I want to recover a little, in fact I have already gained almost a kilo from Occitanie although I am still very fine. I think these grams I've added will do me good for the Tour de France."

Professional cyclists  have long worked to become as powerful but as light as they can in order to maximise performance. However, increased understanding around the effects an energy deficit can have upon the body, hormone production and bone density included, means that riders and teams have become cautious of under fuelling.

Weight loss during a stage race requires a calorie deficit at a time when the body is under stress and in need of good recovery. It is an approach that Team Ineos (then Team Sky) employed with Chris Froome during his Giro d'Italia winning campaign. Froome's weight loss was structured and supervised, but other teams have said that though it's possible for a rider to lose weight during a stage race, they'd not advise it - at the risk of hindering recovery and developing Red-S (relative energy deficiency).

Valverde, who has been a pro since 2002 and riding as strong as ever, last week signed a new contract extending his stay in professional cycling until 2021.

He admitted however, that it is difficult to continue to find the motivation having now become world champion and spent so many years in the sport.

"Carrying [the rainbow jersey] is not all good because it takes away your pressure. You lose tension, also partly because of age and having achieved so many triumphs during my career. I am ambitious and I want to win, but it is true that at this point you have achieved so much that, although you do not want to relax, your head does."

Valverde added that he was "99 per cent" sure he would retire in 2021.