You eat too much before the ride. It is a bike not weight bearing and calories are just not smoked up riding. Drinking too much can cause nausea and mybe you over hydrated. Frankly not eating 5-12 hours before a ride is no problem it has to do with your stores of glycogen in they muscle tissue. Ran my fastest marathons on nothing more than a peanut butter slice of toast 3 hrs before start time. Now I did have my glycogen stores packed from 14 hrs previous of a high carb dinner of 3500 calories or so. It is all about what we eat way before we ride unless the glycogen stores are already depleted. In that case we bonk unless we are highly trained .