Dunno, I just ate at the feed stops on the one I did.
Treated it as 3 separate 33mile rides back to back.
1st 33 miles was flat out as I was late starting,
Middle was done at a leisurely pace
Last 33 miles was a mad dash to the Finnish.
Couple of blocks of flapjack, mug of tea and a banana was enough to see me through at each stop. Felt surprisingly good at the end.
Considering my complete lack of preparation (I did one heavy weekend in the peaks to get tones up, but I'd barely ridden in 2 years). And riding the whole distance with only 70psi in the front tire as I was too lazy to top it up. I only had 1 mechanical which was easily fixed, my cleat came loose so had to be screwed back in. All in all, some people take it all too seriously. I was on a cannondale r500 with some shimano r-550 wheels, some second hand shoes and an mtb helmet.
My entire set-up probably cost less than some peoples front wheel. Invariably these people were taking it very seriously!
So just eat what you want, when you want, its all in your head anyway, if I'd ahve thought about the lack of food maybe i'd have been more tired at the end, but i didn't and I got round just fine.