The main thing with any food eaten on the bike is to only eat a small portion at a time. With Clif Bars, break them into quarters, eat a quarter every 15'-30', no more. But I agree, the texture does get tiresome. Nutritionally, they're excellent as long as one is not allergic to any ingredient. I've done double centuries on nothing but Clif Bars, had a strong ride.

What makes any food easier to digest is to drink water with it. Having trouble? Drink more water and take electrolytes with it. Ever plain water can sit in the stomach if it's not isotonic - meaning having the same concentrations as the blood in the stomach wall.

Other than that, experiment with different mini-mart foods. One's food should be either something one takes with them or be available in every mini-mart. I have a buddy who eats nothing but Hostess Cupcakes on the bike when touring. I like Hostess Fruit Pie at a rest stop. My wife drinks Ensure on the bike. Medjool dates are great. Shot Bloks work. For many riders, Hammer Gel in one of those Hammer flasks is all one needs up to say a 60 mile ride. Some people thrive on Hammer's Perpetuem, others like Hammer's HEED. There are many other powders which make a liquid food. One of the wonderful things about Snickers is that they are available in many countries. We've used them touring quite a bit. Yum.

Also see the DIY food thread, just a few threads down.