I DNF'd the Mille Pennines 1000km Audax on Sunday morning, after completing day 1 and 2; a performance I'm pretty happy with overall, but I'm now looking forward at ironing out the errors I made to go further next time.
Once of the big problems I had during the ride was what to eat, how much and when. When options are limited to petrol stations and shops, what do you favour to keep the energy levels topped up without ending up feeling bloated and sick? Are cycling specific energy bars/gels the answer? I'd rather stick to real food if I can, although I'm open minded to any option.
Just taking a very rough approximation, 1000km will burn about 20,000 calories. That's a lot of food.
Given the general low intensity nature of audax, it makes sense (especially where you are predisposed to gastro upset) to get as much as that from bodyfat as possible.
In order to fat adapt the surest way is go keto, you then have no choice as the brain will fire up it's backup system in the absence of glucose. Even if you switched easily, keto is really hard to maintain in the modern world. You will aslo be slower less powerful all things being equal. (DR Louise Bourke has some research on the body down regulating it's use of glycogen in it's absence and presence of ketones) So if you want to have a fairly quality but not too restricted diet I'd be inclined to
*eat well, not necessarily hflc but, if you are going to eat a good percentage of carbs have them decent with plenty fibre, low gi etc etc. Good clean quality food with minimal sugar, processed foods
* try intermittent fasting, say one day a week when doing something sedentary. Whether any physiological changes happen or not(they probably will) it'll help you mentally when exercising fasted.
* start with a short spin and build up. My first spin was 30km I think. Bring an apple, the world champion of cycling foods, tastier than a banana and rugged as fcuk! A lot of it is in your head, sip water when you think you are hungry.
You will adapt slowly.
*If you feel miserable, eat. It's not a misery contest.
*If you are ever travelling use it as a chance to avoid airport, convenience a do a 24hr fast. If you are used to IF it's surprisingly easy
Adaptation will take a while though so don't dive straight in. I'm at this 3 years or so and if I was riding a 1000km next week over 60hrs or so i'd probably do the following. I'd start each day fasted and consume very little on bike circa 1000-1500 calories over 350km or so. I would then eat a lot when finished with little regard to macros other than adequate protein given the catabolic nature of fasted endurance riding, just eat. Carbs won't be in short supply at any audax control! Same day after.