Terrierman

Yes, most organized centuries have pre-planned rest stops with snacks and water/sports drinks available for you to drink there and also refill your bottles. A lot of them have a specific lunch stop too. Eating and drinking (a lot of drinking) is essential - absolutely essential as in you can't get by without it - for a 100 mile bike ride. If you don't have to stop to urinate several times during the ride, you're not taking in enough liquids. Same way if you feel thirsty, you need to drink more, enough to avoid feeling thirsty. As for the eating, definitely do a good breakfast that will stay with you, like a PBJ sandwich on whole wheat and a banana or a bowl of oatmeal and a banana to start out. During the ride, fruit and easy to digest carbs are the ticket (oatmeal cookies or plain boiled potatoes fill that bill for me), protein the day before but eating meat on a hard ride is a recipe for an upset stomach. Salty foods such as a dill pickle also taste amazingly good during a hard ride. No dairy and total low fat for me to be comfortable.