Like others have said, it depends on how long and hard you are going to ride and how much time you have to eat/digest before you start riding. For me, on weekend rides I will have a glass of water when I get up (before my coffee), then have coffee and oatmeal (with a banana). I typically finish eating 30-45 minutes before I ride. Then I have a 7.5 mile easy ride to where I meet my group. With this regimen I'm usually good for 60-65 miles. If I do a short 60-90 minute ride on a weekday morning, I have coffee, and sometimes eat a couple of handfuls of Cheerios or similar, sometimes not, depending how I feel.