When I was a kid, and I would leave the house for an all-day outing on the bike, I carried a surplus-store plastic canteen and a sandwich, or two, in a bag. If I needed more food, I'd stop and buy a candy bar, or some peanuts, or some such.
As an adult, I fell under the spell of the marketing guys, and started carrying PowerBars and Clif Bars, particularly when training off-road, or racing. The bars tended to make my stomach hurt (mostly due to the rice flour, and rice syrup, probably as I am allergic to rice), and really didn't satisfy me, even though they seemed to give me enough energy to ride.
Still, I tended to wolf down burgers and fries and such foods, after a ride, just to satisfy my craving for "real" food.
Then, I read a few articles about racers in the Classics (Tour de France, Giro, etc.). They eat pasta, sandwiches, fruit, bread, cheese and whatever else they feel like eating while on the bike. Their need for calories is not the only thing that their trainers worry about.
Napolean said that an army travels on its stomach. I think that is doubly true for cyclists.
Through some experimentation, I have found that a number of "normal" menu items sit well in the gut, during excercise. Others, not so well.
Now, on long rides, I pack water, and sandwiches, and cheese crackers...just like I did before I "knew better". And, I not only (usually) make it to the end of a ride with plenty of energy, I don't tend ot eat everything on the menu at the first restaurant I drive by, on the way home.