There are zero grams of fat in a medium-sized banana. An average banana that's seven to eight inches long also contains about 105 calories and 27 grams of carbohydrates, three of which are dietary fiber and 14 of which are sugar.
Bananas are nutrient-dense fruits that help promote cardiovascular and digestive health. They provide a number of vitamins and minerals, including vitamin B6, manganese, vitamin C, potassium, biotin and copper. Their high vitamin, mineral and fiber contents make bananas good snacks for athletes, helping provide endurance if eaten before and during workouts by supplying the energy needed for exercise or training.