On last week's 600k we took banana/chocolate-chip sandwiches and ditto salami/cheese with us. I also had a bidon of Isostar/Overstimm's drink powder and one of plain water. In the HB bag I had the usual bars, plus mini-salami and a bag of crystallized ginger. En route we stopped once for crèpes and once more for steak & chips, otherwise it was sandwiches at roadside halts and for breakfast.
I emptied two sugary bidons over the course, the sandwiches we finished at the last control. I drank probably 6-8 litres of plain water. Of the mini salami enough remained to give the dogs a couple of bits each when I got home, and there's still some ginger and most of the patent bars.
I had one slight suggestion of cramp halfway through the hilliest part of the route, and managed to banish it with copious plain water and a slug or two of sugary.
The moral, I think, is don't rely on one thing only: eat a variety of foods, ordinary meals if they're available and there's time, and never stop drinking.
And bananas are bloody marvellous.
