Mmmmmm......Bananas! Check out the food bags on the Tour etc. They nearly always include a banana. Many riders chuck unwanted items away immediately. I have NEVER seen a rider throw away a banana. Probably the best...and least expensive...of bike snacks.
But now how many bananas can you probably eat on a whole day cycling? My personal record would be around 5 per day, so another banana lover came out of the closet. Anyone?
But yea, a banana is a 250ish calorie shot of energy, mostly carbs, but also some fat and protein. The only thing it would take two bananas to make me feel comfortable.
Beans? No, bananas are ten times better than beans. Many cyclists like bananas. They are quick and easy. You can do a lot with them and are the best source of energy. Nutritionally they have everything you need.
Bananas are great if you ride for a long time. Not only they will energize you but they will also prevent spasm or cramps. Potassium is doing that actually and another natural option would be dried apricot that has even more potassium than bananas.
I agree with you, bananas are for sure a great food to eat while of before doing exercise. Personally, I eat a lot of bananas, maybe two everyday and I can't really go without them!