This might be better stated in terms of time rather than miles, since experienced cyclists might do this in less than two hours, while noobs might take three. Also, experienced cyclists will be better at burning fat rather than carbs for energy. Two hours would probably be about right. In hot weather, add electrolytes regardless of whether sugar is added.

Also, a Clif Bar and two 24 oz. bottles of Gatorade is about 600 calories. I burn more than that on a 25 mile ride, even with the new algorithm that Garmin uses. If a cyclist were to go through this much for a 25 miles ride, s/he'd break even or better in terms of calories burned.