As stated above, everyone is different. My wife can not eat anything solid before or during a ride. She uses those little GU packets.

I used to be able to get up and not eat and do 70 miles without eating. I seem to be able to eat almost anything before or during a ride. I have not tried everything like bratwurst or bourbon. Just recently, I do better if I eat a little about 35 miles into a ride. I still start out on an empty stomach. On centuries, I tend to eat early and often but not much at any one spot.