Each gram of banana contains less than 1 calorie, but bananas may weigh more than 100 grams each. As a low-calorie, high-volume food, bananas fit well into a healthy weight-loss program. By eating bananas along with plenty of fruits and vegetables, whole grains and lean proteins, you can help ensure effective weight management.
Bananas generally range from 81 grams to 152 grams per fruit, and may contain between 72 and 135 calories each. A medium banana -- which is between 7 and 8 inches long -- averages about 118 grams and contains about 105 calories. For perspective, most women who engage in regular moderate exercise burn 1,800 to 2,200 calories each day, and most men with similar activity levels burn 2,400 to 2,800 calories a day.