In short, very.聽
鈥淚f you took one of these racers and you presented him to a normal doctor, without telling the doctor that this rider had just been in the Tour de France, the doctor would think he was on the edge of becoming anorexic,鈥 says Jens Voigt, who recently retired from professional聽racing and is now the cycling analyst for NBC Sports. 鈥淗e would send the racer to a psychologist for counseling. It鈥檚 an artificially low body weight, but the Tour does that to you.鈥
Contenders for the yellow jersey now sport between four and six percent body fat. Let鈥檚 put that in context.聽When people drop below three percent body fat, they run a risk of dying. Many of these racers spend the entire season paring their body weight down so that they arrive at the Tour as lean聽as possible.聽Voigt speaks from personal experience, who says he started each Tour at 4.5 percent body fat and generally finished at 3.8 percent.
Why the fixation with being lean? It comes down to maximizing your power-to-weight ratio. Or, to put that in less egg-headed terms, if two competitors produce the same power on the bike, the lighter one will almost always be able to accelerate and drop their heavier competition on the big mountain climbs, where this race is often won and lost.聽
“You want to be light so you can fly over the mountains, but if you shiver on one bad day in the North, you鈥檙e聽screwed.鈥
In a race decided by seconds, weight matters. A number of Tour de France winners began their careers with entirely unimpressive results, dropped weight,聽and returned a skinnier winner. Miguel Indurain, Bradley Wiggins, Chris Froome, and, perhaps most famously, Lance Armstrong are all examples.聽
鈥淚 was a swimmer and I was always stuck with a swimmer鈥檚 body,鈥 says Armstrong, who started his competitive life as a triathlete and retained a heavily muscled upper body. It was a build well suited to winning one-day races, but which proved a liability in multi-week tours studded with long climbing stages. When Armstrong returned to cycling after his bout with cancer, he was 20 pounds lighter and worlds faster on the climbs.聽
鈥淏eing lean is all about the three or four months before the Tour and鈥攍et鈥檚 be honest here鈥攖his is just about starvation,鈥 he says. 鈥淔or me to get down to 163 pounds and still be four percent [body fat]? I鈥檒l tell you, in those months leading up to the Tour, you鈥檙e just hungry, man.鈥
Being so lean, however, is not only difficult to maintain, but risky as well. A certain amount of body fat (usually around six percent for athletic men) is necessary for maintaining health. With their reserves pushed to the absolute limits, riders who maintain a body fat percentage below five percent for an extended period run numerous risks: muscles atrophy, energy levels plummet and their immune systems take a hit. Sick and worn out during the middle of the Tour is an even greater roadblock to victory than carrying an extra pound of fat.
鈥淏ut here鈥檚 the thing,鈥 says Armstrong, 鈥渋t doesn鈥檛 happen every year, but in the first week of the Tour, the weather can be weird and you can get caught in a cold rain. When guys get聽too lean, they get sick easily because their reserves are so low. So there鈥檚 this dance you have to do鈥攜ou want to be light so you can fly over the mountains, but if you get caught with a shiver on one bad day in the North, you鈥檙e done. You鈥檙e screwed.鈥
When I press Armstrong on the details of his own Tour de France diet, he shrugs the question off.聽
鈥淚f you made a big mistake and didn鈥檛 eat enough the night before the race, that matters,鈥 says Armstrong. 鈥淏ut if we鈥檙e talking about one energy bar over another, or one chef or nutritionist over another鈥 don鈥檛 think it matters. You find something that works for you and you just stick with it.鈥
So what worked for him?
鈥淪troopwafels鈥攋ust these shitty, toxic cookie things that you鈥檇 find right next to the Oreos at the corner store in Belgium. Those are what I existed on during each day鈥檚 race for the last three of four Tours. I liked the taste and it was loaded with calories, probably not the best calories, actually, but I was a creature of habit. It tasted good and I never bonked, so why change?鈥