I don't eat on a very short ride (10-15 miles) but more than 20 and I start snacking. If I'm going to stop somewhere, I bring a Luna bar or trail mix. Circle K stores sell bananas for 25 cents! I also have found shot blocks are convenient and easy to digest.
I haven't done a full century yet, but about a month ago I did an organized 73 mile ride. I prefer real food - and to be honest, I don't like the GU very much at all, but it's easy to eat while I'm riding, so I alternated between 3 shot blocks and a packet of GU every half hour and I did not ever feel tired or hungry during the ride. I stopped at one aid station and had a banana- but otherwise rode straight through.
I sometimes make or buy a smoothie or a mocha frappucino after a long ride, especially when it's hot out.
Last year when I was focusing on weight loss, I tried to make it through a weekend with a 45 mile ride and a 25 mile ride with only about 200 extra calories. Sunday afternoon I so ravenous I could not concentrate on anything other than finding something to eat. I don't recommend that approach!
2016 Specialized Ruby Comp disc - Ruby Expert ti 155
2010 Surly Long Haul Trucker - Jett 143
I know there are articles that state that vegans will get enough protein in their diet if they just eat healthy and balanced. But, I find that when I am riding long if I stress protein for my after ride meals, I can lose some of the feeling of "oh look there is some food, I should eatt it...oh, more....more...look there is some there under that rock, let me dig it up...food....eat...."
I use a good soy-milk chai as my recovery drink and add extra nuts to dishes (e.g., stir fry, Indian-style dishes, and even american-style casseroles). We've also add TVP as a thickener to sauces that might not need it normally or add seitan or chunks of tofu to soups that could stand on their own. For work when the unreasonable craving starts I have some seitan jerky in my desk drawer. With a protein kick, the cravings subside; when I used veggies or carbs, they just kept going.
2009 Waterford RS-14 S&S Couplers - Brooks B68-Anatomica - Traveller
2008 Waterford RS-33 - Brooks B68-Anatomica - Go Fast
2012 Waterford Commuter - Brooks B68-Anatomica - 3.5-Season/Commuter
2011 Surly Troll - Brooks B68 Imperial - Snow Beast