How to fuel a cycling Grand Tour: Carbs!

How to fuel a cycling Grand Tour: Carbs!

Feb 2022
How to fuel a cycling Grand Tour: Carbs!

The most gruelling and challenging event a pro cyclist will face in the racing calendar is competing in a Grand Tour like the Tour de France, Giro d’Italia or Vuelta a España. Why? Because a Grand Tour demands a rider to cover approximately 3,500 km across 21 stages in just 23 days, which is the equivalent of riding from Land’s End to John O’Groats two and a half times! This epic endurance endeavour is as much a nutritional challenge as it is a physical challenge. Ensuring a rider is eating enough of the right types of foods to not only complete the race but also compete at the highest level is a fine balance that’s easy to get wrong. I got to experience the logistical, technical and psychological challenges of working at all three grand tours during my time in elite cycling, this is what I learnt and how we apply it in hexis. 

To get through a Grand Tour you just eat as much as you can…..right? Maybe not! 

There is no doubt that cyclists eat a LOT given the amount of calories they burn day to day in a Grand Tour (an average of ~3500 kcal during each stage). However, as with every sport and every athlete, nutrition it's not a one size fits all solution. Each stage of a Grand Tour will require a different amount of energy from the riders, with some stages being long, some short and some mountainous with long hard climbs. In addition a cycling team is made up of riders with different specialties, some are good at climbing mountains, some are good at time trials and then you have the riders who are good at it all (they normally go for the overall win). Depending on their specialities riders are given a different job each day to best support their team. For example riders who are good at climbing will not be expected to do a lot of work for their team on flat stages that are better for sprinters. All these things mean that riders can burn very different amounts of energy on different stages, depending on the stage type and the riders job for that day. During the Vuelta a España in 2021 we recorded all the data for one of the mountain climbers to help demonstrate how there can be massive swings in energy and carbohydrate intake day to day during a grand tour. 

So how big can this difference be? Well on the “easiest” day, which was a recovery day, he burned 560 kcal equevelent to 2 cheeseburgers whilst on his bike, on stage 20 he burned 5830 kcal which is equivalent to 20 cheeseburgers!!! 10 times more energy was needed during stage 20 than was needed for his recovery spin on the recovery day. That of course means that the food he ate and the total energy he needed was completely different between those two days. To add some context to these numbers, this rider had 340g of carbohydrate in total on his rest day, he had 1.1kg of carbohydrate during stage 20. That isn’t the amount of food, that’s just the carbohydrate content, to get 1.1kg of carbohydrate from cooked white pasta you would have to eat about 2.8kg! So you can see that these athletes are eating machines as well as incredible cyclists. Hopefully these extremes highlight how dynamic the nutrition recommendations need to be in order to help a rider get through the stage they have today, but also think about what is coming tomorrow and what preparation is needed to make sure they have enough energy in the tank to do their job. 

What are the risks of under or over-fueling?

Under fueling is most obvious when a rider doesn't take on enough carbs and calories. They are going to get to a point in a big climb or critical point in the race and (in the words of Michael Kane) blow your doors off! It can be hard to watch but you see it when a rider is completely spent and looks like they are going backwards compared to the others around them. This can happen because they didn't refuel after the stage the day before, or they didn’t fuel well enough at breakfast, or during the earlier parts of the stage. During the intense part of the stage when their body is heavily reliant on carbs for energy the reserves are just not there to fuel the intensity they need (check out “Why exercise intensity MATTERS” for more detail on this). 

The risks for over fueling are all about power to weight. The riders take several weeks to slowly reduce their body fat prior to a grand tour so that their power to weight ratio is high. The reason we want to avoid over-fueling is that if the rider puts on weight then they can lose that edge that they worked so hard for in the build up to a race. This highlights why each day in a Grand Tour should have its own nutrition recommendations, if we had given the rider the same amount of carbs and calories on his rest day as we did on stage 20 he would have been in a massive calorie surplus, which he didn't need. 

How technology is advancing personalised performance nutrition

All professionals and a large number of amateur cyclists now have power metres and GPSs on their bikes and a heart rate monitor on their chest, with the data generated from these devices we are able to get a measure of the energy expended during a training ride or race. After each stage of a Grand Tour the riders are able to upload all their data which can then be used to help calculate nutrition recommendations. We did this during the Vuelta a España in 2021 to provide personalised feedback about in race fueling as well as specific recommendations for the amounts of foods riders should eat to ensure they recovered from the stage, didn’t over fuel but were prepared for the next day. 

Providing this level of nutrition support required the team of chefs, coaches and the nutritionists to work collaboratively on a custom made cloud based system. Between us we were able to deliver the level of detail required to provide truly individualised recommendations in as close to real time as possible. This ment the athlete had all the information about foods and plans for tomorrow when they needed it. This system works well for professional athletes, and we were able to support about 20 athletes at any one time, often supporting multiple race programmes across both mens and womens teams simultaneously, but providing this level of detail requires a lot of calculations which take a lot of time! 

How the  lessons learnt at Grand Tours are translated into hexis

Seeing that this level of personalisation can be done at the professional level has driven the team at hexis to build technology that enables us to provide personalised nutrition recommendations for the everyday athlete all the way up to the pro’s competing in grand tours. We were able to bring together our skills in computer science, biostatistics, digital behaviour change, physiology and nutrition to create a platform that supports an individual based on their lifestyle, training and performance goals. More often than not each day has a different calorie and carbohydrate requirement, training days will need more calories and carbs than rest days, and hard training days will need even more. Figuring out how much you need each day is what hexis was designed to do. 

Dr. Sam Impey

Performance Scientist

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Dr. Sam Impey