Not planning to enter many events next year but I may enter the Edale 98 Edges. I'm hoping to complete the Sandstone Trail at some stage next year and put some work into the Welsh 3,000 course with a view to doing it in 2020.
Look at what Kilian ate for his 24hr skimo ascent/descent record. Basically a ton of gels. I suspect he finished strongly .
Many times I run without having anything to eat beforehand and then the body adapts on ways to save energy and ways to use the energy in your body. If you are used to eating a lot all the time when you are running then if you run out of food or you miss a feed station in a race then your body is not adapted to performing without food. But if you are used to running for a long time without food your body is always saving some energy or using its stored energy to perform better.
Being 'bellyful' adapted is a useful skill to have. When I was doing longer stuff more regularly I'd get up, get dressed have a drink and go ...or have something to eat, fanny about for a short while and go. Both useful strategies. It might be quite different if you're working harder but my long strategy is 'don't get out of breath'. I've struggled a couple of times through not eating enough, eg bad weather and you're concentrating too much on getting your head down. Even if you're making a mental note to eat every hour, it can soon pass too long if you're busy navigating or just in your own world with your hood up. Suspect I'm better suited to force feeding than being fat adapted.It really takes all sorts - Nicky Spinks famously tucked into fish and chips on her double BGR. A mate of mine did his on nothing but Kendal Mint Cake. Not sure if he still has any teeth. https://www.trailrunningmag.co.uk/training/nutrition/article/nicky-spinks-double-bob-graham-diet
I'm sure I'm teaching you to suck eggs but the aim is to have both fat and carb burning pathways open (unlike keto) so that you can fuel longer lower intensity efforts mainly off fat (in House's world this is getting to the crux pitch on your alpine objective, but could easily be the flatter bits of a long run) and then fuel with carbs for more intensive parts of the day or training.
Anybody in for the Newlands Memorial this Saturday? I will be if I can get a race entry.
I'll try to get a suitable light pack/vest for carrying my water/layers/food etc..