I did the Fellsman for the first time last year and I took *way* too much food. I hadn't done many long events where food was provided so I wasn't sure how much to rely upon the checkpoint grub, so I erred on the side of caution. As it was, I didn't really need much else at all, as there was plenty of food provided and there was generally something that I could stomach - I ended up eating my own food mostly just so I didn't carry it all the way round!
This year I will probably just carry a bag or two of jelly babies (as well as the emergency 300g) and will primarily rely on checkpoint food. I think, through luck rather than judgement, I got my nutrition right last year as I found it fairly easy going and didn't have any significant lows. I hope I manage that trick this year, particularly as I may not be as fit.
I have vivid memories that the spaghetti hoops I had at about half way being the tastiest I have ever eaten...