Feeding for the Bicingles challenge

Feeding for the Bicingles challenge

On 22nd of June Charles is going to attempt an endurance cycling event called the Bicingles challenge which involves cycling up Mt Ventoux in Provence six times in a day. This is the equivalent to riding up Everest from sea level, and is tough, in fact fewer people have succeeded than have been into space!

Fortunately Charles' first degree was in physiology and he went on to study sports and excercise medicine, so he is in a good position to work out how to stand a chance. This one wont be easy...

Charles has done lots of measurements and when cycling hard he uses about 1000 calories an hour provided there is not too much heat stress. In the hot temperatures of Provence (28°) plus wind it may be a little more. He hopes to be finished in about 20 hours but may take a little more, if its more than 24 then it is a fail!

Charles estimates he will need about 20,000 calories in the day. That’s is 10 days worth of food for a normal man! The picture shows what he has packed to eat on the day, but this is only 10,000 calories.

Unfortunately, the human body can only absorb about 60 g of glucose an hour, but with a very specific mix of glucose and fructose of the 2-to-1 ratio coupled with some sodium, uptake can be about 90 grams per hour. This is because glucose and fructose have independent transporters for absorption from the gut, and both need some sodium to work.

Each gram of carbohydrate will yield about 4 calories therefore Charles will be able to take on about only 360 calories per hour, or 7200 calories in the 20 hours. The food Charles has chosen has all been developed to be easily absorbed, with that glucose fructose mix.

This leaves quite a gap in terms of what can be absorbed during the ride and what is needed to keep going at a sufficient pace.

Some of this can be made up by the body’s natural store of carbohydrate in the form of glycogen. This is stored both in the liver and in the muscles. About 120 g can be stored in the liver of a well-trained athlete and about 400 g can be stored in the muscles so Charles can expect to start the event with about another 2080 calories of carbohydrate stored. He has been using a three day carbo-loading regime involving glycogen depletion with long fasted workouts followed by a high carbohydrate low-fat low protein diet (about 90% carbs 5% fat 5% protein) looking to take on about 450g of carbohydrate per day.

The remainder of the energy requirements are going to need to come from body fat and in order to help with this Charles has been using “butter coffee” or “bullet proof coffee” for a number of weeks now to help switch his body to being “fat adapted“ by eating only black coffee with butter and coconut oil mixed in with no carbohydrate for a long period research has shown that the body gets used to using this fat as a fuel source.

Charles has been doing this for a period of about eight weeks just living off this for breakfast and lunch with a normal dinner and as disgusting as it sounds it works very well indeed and it tastes ok! This has also helped him hit his target of about 9% body fat for the event. He is very much looking forwards to a normal diet again though!

Time will tell whether all of the strategies help Charles on the big day to achieve what is said to be one of the greatest challenges in cycling, but the science and physiology are on his side.

Posted on Jun 14, 2019

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