On Polaris trailquests where you ride for 7 hours on the Saturday then 5 on the Sunday, my problem was always hunger, not energy. In the days we used to do them (early 90s) there were few sports nutrition products but we had already cottoned on to maltodextrin and found a bulk source, so we used to put that in our drink and eat dried bananas, which look disgusting. The energy wasn't a problem but by the end of the event we would be starving; I remember on one overnight event we carried steaks, which we cooked in our tent and we were surprised at how much better we felt the next morning. We also discovered Build Up and Complan, which are recovery drinks for convalescents based on maltodextrin. Years before that I walked the West Coast Trail on Vancouver Island, which was five days self-supported with little chance of buying food, so we carried dried meals and cup-a-soup, which we found to be very energising as a quick snack in the middle of the day - later realising that the major ingredient is good old maltodextrin again. I wish that in those days I had known what I know now about energy and recovery foods, the events would have been so much easier. Wish I'd been a roadie in those days too as I'd have done much better at the mountain biking events.