Our riders have looked down at their Wahoos this week and seen temperatures nearing 40 degrees celsius. When the Tour hits the Alps in the final week of the race, the heat will become even more oppressive, sun melting the asphalt on steep, sustained climbs, which our riders will race up with little wind to cool them.

Eating and drinking on such days is an enormous challenge. During a mountain stage at the Tour de France, riders can burn over 10,000 calories and lose several liters of fluid to sweat.

EF Pro Cycling nutritionist Will Girling helps our riders manage their intake of food and drink on and off the bike so they can perform in such extreme conditions. These are Will’s top nutrition tips for riding in the summer heat.

Hydration is not just a matter of drinking lots of water. Your body’s fluid balance is affected by concentrations of electrolytes such as sodium and magnesium, which are vital for maintaining nerve and muscle function. You lose electrolytes when you sweat. Athletes need to replace those electrolytes in order to remain hydrated during exercise and continue to perform at their best. This is especially important for ‘salty’ sweaters, who lose more electrolytes than others and thus need to consume more to return to their natural levels. Our Amacx energy drinks are specially formulated with added sodium and magnesium to help our riders maintain their fluid balance in the heat.

During a Tour de France stage, our riders will drink at least one liter per hour to prevent dehydration. Studies show that aerobic performance will be negatively affected if they lose as little as 2% of their body weight to fluid loss. Will monitors their hydration rates throughout the race to make sure that they don’t get dehydrated. He ensures that they drink enough pre- and post-race and that they replace lost electrolytes to maintain their fluid balance. Since rates of electrolyte loss differ between athletes, he has done individualized sweat testing with each of our riders using Nix Biosensors to know how much they each need to consume.

“The most important thing for the average person to think about is that you need to think about hydration and sodium together,” Will says. “If you're going out and riding in the heat, you will lose both fluid and sodium in your sweat. If you then replace that fluid but do not replace the electrolyte, the remaining sodium you have within your body will get diluted within that fluid you're taking on board. If you continue to do that, you are then opening yourself up to the potential of hyponatremia, which is dangerous. If you're drinking more, you need more sodium to go alongside it.”

Consuming cold drinks and food is one of the most effective ways to avoid overheating. An icy drink will go right to your core to help bring your body temperature down. Our team Cadillacs at the Tour de France are each outfitted with electric coolers, so our riders can get ice-cold drinks when they are suffering up the hottest climbs. We also use Amacx ice gels, which contain 30 grams of carbohydrates with a 2:1 ratio of glucose to fructose for better absorption as well as 200 milligrams of sodium to aid hydration. Our riders love these ice-gels, which are like frozen popsicles for athletes.

“We do a lot of core cooling,” Will says. “We have an ice slushie maker that we'll have this year on the bus, so that we're able to bring that core temperature down right away after a stage. The more we can bring that core temperature down, the more normalized they're going to be, so their appetite should come back more. We also try to get more calories in through drinks like smoothies and fruit juice, because we really want to drive both hydration and calories that they can take in from formats that aren't too filling. On the bike, they definitely shift more towards gels instead of bars, because they are easier to eat in the heat.”

During a Tour de France stage, riders will consume up to 120 grams of carbohydrate per hour to maintain blood glucose levels and improve recovery on following days. It’s especially hard to eat and drink so many carbs on the bike when it is hot and you are racing flat out. Stomaching solid food is difficult. That’s why our riders turn to the easiest-to-digest sources, like Amacx energy gels, fruit chews, and drinks. Their 2:1 formula of glucose to fructose is optimal for absorption and they come in delicious flavors like cola, cassis, and strawberry. Amacx gels are especially effective, because they have been designed in a drinkable format with water and electrolytes, so they don’t need to be consumed with additional fluid.

“Our riders definitely shift more towards gels, just for preference, when it is hot,” Will says. “Your heart rate will increase because of heat, increasing the intensity of the effort. More blood will move to the surface of the skin to help dump that heat, so it's going to be harder to digest things, so you want to consume foods that are less filling on the bike. Our riders will still eat solids, but tend to prefer bananas or fruit chews on the bike instead of something like a rice cake.”

Hot weather suppresses appetite. Nevertheless, it is still crucial for Tour de France racers to replenish all of the calories that they burn during a day. Making meals that they want to eat is a challenge for our team chef, Owen Blandy, who works with Will to design healthy and nutritious daily menus for our riders. They will eat cooler foods on hot days at the Tour de France. Owen will prepare smoothies, cold soups, pasta salads and other refrigerated dishes so that our riders can take in all of the calories they need without getting uncomfortably hot.

“We change the riders’ menus to fit the hot weather,” Will says. “Their appetites do get suppressed, so we want to make meals as palatable as possible. There will be more carbohydrate and calories available in drink format, to help them with that, and food does tend to be lighter. The meals we make tend to be a little bit lower in fiber, a little bit more zesty, a little bit more fresh for their palates.”

To learn more about what our riders eat during the Tour de France watch 'A Day in the Life of a WorldTour team chef' on RaceTV