How many calories in a banana

How many calories in a banana
Bananas are rich in certain nutrients, and they are one of the best sources of Potassium in the diet. They are also rich in Manganese, Magnesium  and Vitamin B6. They do contain many other nutrients but in smaller amounts.
They contain almost no fat or protein and the majority of calories in them come from  carbohydrates The carbohydrates in bananas are mainly from starch and the simple sugars glucose and fructose. Bananas also contain a few grams of fiber.
Bananas are usually categorized based on their size, as extra-small (<6"), small (6-7"), medium (7-8"), large (8-9") and extra-large (9"+).
 How many calories should I eat 
How many calories in a banana, based on size?
  • Extra-Small Banana (81g): 72 calories, 19g carbohydrates, 1g protein
  • Small Banana (101g): 90 calories, 23g carbohydrates, 1g protein
  • Medium Banana (118g): 105 calories, 27g carbohydrates, 1g protein
  • Large Banana (136g): 121 calories, 31g carbohydrates, 1g protein
  • Extra-Large Banana (152g): 135 calories, 35g carbohydrates, 2g protein
The glycemic index and the ratio of starch to sugar will be different depending on how ripe the bananas are. As the banana ripens, more and more of the starch is turned into sugar.
Bananas are low on the GlycemicIndex (less than 55), but this depends on the ripeness. Under-ripe bananas are very low, while ripe bananas can get into the medium range.
They have a low Glycemic Load but a higher Insulin Index than many other fruits.