I eat just bread or cereal. Either toasted or not. Could be plain toast, english muffin, or a bagel. Orr cereal or oatmeal.

A lot of people I know don't eat. As long as my ride is under 60 miles I am fine with just the pre-breakfast and fluids in my bottles, anything longer and I tend to need a little more, which I prefer to take in on the bike instead of before the bike.

Also slowly change what you eat, some people have digestion issues while on the bike, and you might not realize it until it is to late.

For me, I can't have coffee or peanut butter before I do any ride that includes intervals, tempo work, or any other hard efforts; but I can have it if I am just doing a recovery or lsd ride.