One kilo of carbs a day: how riders fuel on hard, Alpine stages at the Giro

Although he faded 8km from the finish line, Bora-Hansgrohe's Lennard Kämna had animated much of stage 16 of the Giro d'Italia – a thrilling 202km with 5,200m of climbing from Salò to Aprica. Already a winner on stage four atop Mount Etna, the German rider had been in the breakaway for 157km.

What exactly did he – and the other Bora-Hansgrohe riders – eat and drink to support such a strong performance? And did he miss some fuelling in the end, or were his legs just unable to match the rest of the field in the last climb to Aprica?

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The help of technology 

"We forecast [the athletes'] energy expenditure for the stage and the energy they need to get through that stage with performance software. And, of course, we try to fuel them well with carbohydrates. So it's nothing new, but it's still super important," says Robert Gorgos, head nutritionist at Bora-Hansgrohe.The riders' energy expenditure calculation is a forecast of what they're expected to burn during a race at a specific intensity. It's calculated from metabolic tests they've performed during the season, which can let them know with great precision how much carbs and fats riders consume at a given power output. This kind of software can also consider discrepancies due to altitude, and though they're not 100% precise (as even labs are not), they're still reliable, and teams have been using them successfully.

Timing and 100 grams per hour would do

But Gorgos and his team not only take into consideration the power output and the time spent in the saddle of their riders; to better understand what they need during the day, they also track what they eat at breakfast, after the stage, and dinner. That's important because races can reduce carb absorption.

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"On such a hard day, during the climb, the absorption of carbohydrates is reduced because of the high intensity," he says. "So they have to try to feel well on the easier parts. For example, they take a gel just after a GPM before going in the descent or eat some solid food during a flat section."Gorgos says that around half of what they consume in these stages comes from carbohydrate drinks – then gels and some solid food, in that order. And on a day like stage 16, riders consume more than 100 grams of carbohydrate per hour for the entire six hours of racing. The rest is consumed at breakfast, immediately after the stage, and at dinner (around 200g at breakfast and dinner). But it's always hard to keep up with the substantial energy expenditures, and riders often lose weight during Grand Tours.

"When you calculate that a small rider (60-65 kg) may consume 6000 calories during the stage, you have to make sure they eat at least 1,100/1,200 grams of carbs during the day [breakfast, in the race, and after]. And that's close to 5,000 calories. The remaining energy comes from fat and protein," Gorgos explains.

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Race and post race fuelling

At the end of the stage, it's also paramount to know exactly what the riders consumed during the race. In this way, they can adapt post-race fuelling, dinner, and the following breakfast to make sure riders do not end up in a high energy deficit that would be detrimental to performance.

"In long stages," says Gorgos, "the carbohydrate intake is crucial for their overall feeding. That's because there is less time to eat outside of the race, so if a rider only eats 200 grams of carbs during the race, there's no chance they will be able to digest 1,000 grams of carbs outside of it."

Type of carbs and hydration

The type of carbohydrates they consume also makes a difference. For hard days they go for less healthy options (with fewer fibres) but easier to digest and get used by the body. Then, on the other hand, they switch and get more fibres in on easier days.

on top of fuelling, there's hydration, which is equally important, particularly on hot days. 

"In stage 16, which was not hot, they consumed between eight and ten bidons of around 500-600ml [4-6 litres of fluids in total]. For a hotter day, it's a little more than that, so the drink's concentration [water and carbs ratio] is a little bit lower than when it's cold, where the concentration is a little bit higher. On hot days, they also need to cool down their bodies, so they pour a lot of water over their head, legs and socks."

Did Kämna blow up?

Finally, in the specific case of Kämna being caught back at 8km from the end, Gorgos doesn't necessarily believe it was a fuelling problem.

"He was still able to hold on to the second group after he got caught and tried his chances in the descent," he says. "It's just a super-hard race against the best riders in the world. If you have it in your legs, you have it, and if you don't, you don't. And one day you have it, the other day not."

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With one more mountain stage to go, Kämna might still have it. Provided he’s fuelling well.