We rode 14 miles up and down some rugged mountains this past sunday, lots of mud, rocks, and roots. Not as far as your race but its knarly ridin' and I am wiped after the 3 hr ride. As another poster indicated I find I do best with a big breakfast of egg omelette, bacon, and kefir smoothie. I too carry a larabar just in case but have been using pemmican and sometimes coconut macaroons. In the winter or late fall I use the primal bar recipe on this site, right now too warm and it melts.
You'll never see the light if you're in someone else's shadow, or said another way, life is like a dog sled team, if you're not the lead dog, the scenery never changes