I'm not currently running and, even when I am, I don't do it for any great distance.
For my longer rides, I carry one bottle of Cytomax Sport and one bottle of water. I've never really liked gels and ten to stick to real food. Bananas are probably my first choice. Easy to eat, easy to carry.
I've worn braces since late 2007 and that somewhat limits what I can eat during rides because I don't really like the sensation of having a bunch of stuff stuck in my braces and teeth. I used to rely heavily on Clif Blocs, but I struggle with them because of my braces. If they're soft, I do okay though.
For my longest of rides--RAIN for instance--when the official SAG stops are few and far between, I keep cut up Payday bars in my top tube bag and eat a square of it every 20 minutes or so. If there are official stops, I might have a PB&J or fruit, maybe a cookie or two or some trail mix. I never eat a lot at one time during a ride.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher