It can be specific to the individual and there training. Many who have been long time endurance athletes do not need to eat or drink that much unless things get really long. A 60 mile ride on a cool day I can finish with no liquid at all and I never need to eat for something 60 or less. Now if I was racing that would be different and if it is really warm and humid. Then I need a large bottle of crystal light about 1/2 liter per hour but it would be more if I was eating and riding a century. To be sure though the night before I generally eat a pretty large dinner so the energy stores are in the body specifically the glycogen in muscle.
Consider this interesting stat. The world record for a marathon on a track was done by an African runner who ran in just under 2 hours 26.2miles. He never took a drink yet was running sub 5 minute miles. In fact there are numerous examples of this, and while it may not be smart or the best way to do things, but it has been done routinely.