Actually, fruits are pretty empty foods Sezei. How often have you eaten fruit and thought, "oh man I am stuffed"? They are basically just water and sugar. A lot of people use them as a snack substitute which is a hell of a lot better then eating junk. However, for those who have even more willpower, sacrificing the fruit alltogether and eating vegetables instead will not only save you in calories but will also have a hell of a lot less carbs.
Bottom line. Are bananas bad? Course not. Are there better foods to eat instead bananas if you are trying to shed off bodyfat? Yes. Obviously if you are not trying to lose bodyfat and your goal is just to eat healthy, then eat those bananas without any shame
