I prefer starting the day with some oatmeal or something similar, having a light lunch at a country store or just along the road if necessary and then making a supper of lentils and ham or something similar in the evening. In between, I'll carry fruit leathers and trail mix and fruit and I'll stop several times for a snack. On a hot afternoon, if I see a small store, fruit stand or campground with ice cream for sale, I'll often stop in for a rest.
I don't eat junk food or fast food along the way since those things will make me feel sick. And I try to balance out what I'm eating.
On the road, it's a good idea to carry some snack food for energy. It's much more important to carry a lot of water, especially in summer when temperatures reach 40 C.