Some of the athletes recently have been clocking up 4,000-5,000m of vertical – day after day. That's the equivalent of climbing from sea level to the summit of Mount Everest every other day. 

Unsurprisingly, then, it's hungry work and athletes consume up to 6,000 calories daily (an adult male normally requires around 2,500).

Every athlete has their own nutritional strategy. Some, such as Simon Oberrauner (AUT2) have gone vegan for the race. As Tom De Dorlodot (BEL) says: 'Don’t forget to eat! With a lot of effort, all those calories vanish… During my first Red Bull X-Alps, I lost 10kg, basically a kilogram per day. I now pay much more attention to what I eat. I even have a nutritionist who helps me with a good menu plan for the race.'

And Gavin McClurg (USA1) barely stops eating. 'I eat whole, real food whenever I can. I find my stomach can’t handle food if I eat and immediately do a bunch of vertical, so my daily plan typically goes like this. I have coffee with MCT oil as soon as I’m out of bed, before heading out the door for the morning walk up to a sled ride launch. Then a protein shake with a ton of good stuff (avocado, banana, almond butter) when I can take a break, before a proper breakfast if there’s time. I also take something I can eat in the air for the big flight of the day. I then have a MASSIVE dinner, during which I eat as much as I possibly can, especially protein and fat. Carbs have their place, but in 2015 I lived on energy gels and my body couldn’t dump the swelling. Eating crap over a 12-day race will take its toll.'

See how all that food translates into action on Live Tracking.