This may sound weird, but practice eating and drinking on the bike. Not just the physical act, but get your system used to eating while working and make sure you are drinking enough. A lot of people (me included) have a difficult time eating while exercising. I don't feel hungry, in fact I often feel like food is off-putting when putting in a strenuous ride, so I have to be careful to not bonk. You'll be a much happier camper the whole way through if you keep yourself fed and hydrated. Experimenting now will give you an idea of what foods and drinks work best for you too.