When your starting out with this sport you should always keep yourself fueled up for the big rides, there is nothing worse than hitting the wall and running out of energy during your ride. It does not make for an enjoyable day out and you are not doing yourself favors, especially if your cycling on consecutive days doing a mini tour or such. To really get the most from your body, start in the weeks, or rather months, beforehand with regular riding to make your body fitter and better at using its fat stores. Fit riders use higher amounts of fats and are more efficient at stretching out carbohydrate reserves. Use this simple reminder about what makes you fitter: A B C. That is, Aerobic riding four to six hours a week, Breakfast-less rides for up to two hours to make your body fat-burning savvy, and Consistency. As far as snack go, just anything to give you energy and substance i.e. carb and fat content, my personal is a snickers bar or flapjacks.