Here are a few nutrition tips from Mark Liddle mountain biking enthusiast and former Event Director of the 2017 UCI MTB World Championships:
” To be at your best you should “top up your batteries” in the days before the race by eating high carbohydrate meals (rice, pasta, oatmeal etc.), and you should increase the amount of water you drink for a few days in advance. Doing this will make sure that you have as much stored water and energy as you can for the big event.
The other big thing is when the race is going to be longer than 90 minutes, follow the counter intuitive rule of “Eat before you’re hungry and drink before you’re thirsty”. It can be difficult to get a sense of when to eat and drink so I find it can help to schedule time at regular intervals, say every 20 minutes after the 40 minutes to eat a small amount and drink around 100ml of water.
There are loads of other things that you could delve into but if you think about these two rules then you’ll get a long way to success. If you want to dive a bit deeper Sports Dietitians Australia have a detailed fact sheet here. ”