Bananas are a healthy source of fiber, potassium, vitamin B6, vitamin C, and various antioxidants and phytonutrients.

Many types and sizes are available. Their color usually varies from green to yellow. However, some varieties are red.

Nutritional Values

Nutrition facts for 1 medium banana (100 grams) (1):

Calories: 89

Water: 75%

Protein: 1.1 grams

Carbs: 22.8 grams

Sugar: 12.2 grams

Fiber: 2.6 grams

Fat: 0.3 grams


Bananas are a rich source of carbohydrates that occur as starch in unripe bananas and sugars in unripe bananas. The carbohydrate composition of bananas changes greatly during ripening. The main component of unripe bananas is starch. Green bananas contain up to 80% starch measured by dry weight. During ripening, starch is converted into sugar and less than 1% when the banana is fully ripe. The most common types of sugar in ripe bananas are sucrose, fructose, and glucose. In ripe bananas, the total sugar content can reach more than 16% of the fresh weight. Bananas have a relatively low glycemic index (GI) of 42-58, depending on their maturity. The GI is a measure of how quickly carbohydrates in food enter your bloodstream and build up blood sugar.


A high proportion of the starch in unripe bananas is a resistant starch that passes through your undigested gut. In your large intestine, this starch is fermented with bacteria to form butyrate, a short-chain fatty acid that appears to have beneficial effects on gut health. Bananas are also a good source of other types of fiber, such as pectin. Some of the pectin in bananas is soluble in water. As bananas mature, the proportion of water-soluble pectin increases. Both pectin and resistant starch attenuate blood sugar spikes after eating.

Vitamins and Minerals

Bananas are a source of many vitamins and minerals, especially potassium, B6, and C.

Potassium; Bananas are a good source of potassium. A diet rich in potassium can lower blood pressure in people with high levels and benefit heart health.