Low calories and fat but high fibre. Although bananas are a little higher in calories and carbohydrates some fruits, they are not condered a high-calorie food. A medium banana has around 92 calories, less than many diet snack foods that contain around 100 calories. Bananas also contain very little fat,about 0.5 grammes in one banana, but are very high in fiber. They are also rice in potassium as well as vitamin A,a wide range of B vitamins, vitamin C, folic acid, magnesium and calcium. So bananas contribute to a healthy and balanced diet whether you are truing to lose weight or not