we're just back from a 3 day hike in north Wales, it was cold wet and hilly - perfect
it's our first hike since I went primal about a month back and I was amazed how little I ate! We had a big breakfast each day (bacon) then I was fine till lunch (meat & nuts) and again no snacking till dinner (re-hydrated ration packs, leaving the carbs to my wife). I guess my body must be burning it's own fuel rather than relying on hourly energy bars or crackers. We walked slightly slower than normal, but really not much. Experiment with it in the run-up to your big trip, you might be surprised too!