Are Bananas a Healthy, Low-Calorie Snack?

By Adda Bjarnadottir

Bananas are one of the most popular fruits in the world.

They are extremely healthy and contain several important nutrients.

People generally know that bananas are very nutritious, but many wonder how many calories and carbs they actually contain.

This article answers those questions.

How Many Calories Are in Various Sizes of Bananas?

A medium-sized banana contains 105 calories, on average.

However, different sizes of bananas contain varying amounts of calories.

Below are the calorie contents of standard banana sizes (1):

• Extra small (less than 6 inches, 81 grams): 72 calories.

• Small (6–7 inches, 101 grams): 90 calories.

• Medium (7–8 inches, 118 grams): 105 calories.

• Large (8–9 inches, 136 grams): 121 calories.

• Extra large (9 inches or longer, 152 grams): 135 calories.

• Sliced (1 cup, 150 grams): 134 calories.

• Mashed (1 cup, 225 grams): 200 calories.

If you’re unsure about the size of your banana, you can estimate that an average-sized banana contains about 100 calories.

Ninety-three percent of a banana’s calories come from carbs, 4 percent from protein and 3 percent from fat.

Bottom Line: The calorie contents of bananas range from 72–135 calories. An average-sized banana contains about 100 calories.

How Many Carbs Are in a Banana?

Bananas are almost exclusively composed of water and carbs.

Those who watch their carb intake are interested in knowing the carb content of their food.

Here is the carb content of standard banana sizes and amounts (1):

• Extra small (less than 6 inches, 81 grams): 19 grams.

• Small (6–7 inches, 101 grams): 23 grams.

• Medium (7–8 inches, 118 grams): 27 grams.

• Large (8–9 inches, 136 grams): 31 grams.

• Extra large (9 inches or longer, 152 grams): 35 grams.

• Sliced (1 cup, 150 grams): 34 grams.

• Mashed (1 cup, 225 grams): 51 grams.

Bananas also contain 2-4 grams of fiber, depending on the size. You can subtract 2-4 grams if you are looking for the “net” carb content (net carbs = total carbs – fiber).

Additionally, a banana’s ripeness may affect its carb content.

Generally speaking, green or unripe bananas contain fewer digestible carbs than ripe bananas.

Bottom Line: An average-sized banana contains about 25 grams of carbs, perhaps even less if the banana is unripe (green).

Unripe (Green) Bananas Contain More Resistant Starch

The main nutrient in bananas is carbs, but the carb composition changes drastically during ripening.

Unripe bananas contain high amounts of starch and some of that starch is resistant starch (2).

Because the starch in a banana is converted to sugar during ripening, yellow bananas contain much less resistant starch than green ones. In fact, the resistant starch content of a fully ripe banana is less than 1 percent (2).

Resistant starch is a type of indigestible carbohydrate that escapes digestion and functions like fiber in the body.

It reaches the colon undigested, where it feeds friendly gut bacteria (3, 4).

When the bacteria digest resistant starches, they form gases and short-chain fatty acids (SCFA), which are important for digestive health (5, 6).

About 95 percent of these SCFA is then rapidly absorbed by the cells in the colon and used by the body for energy (5, 7, 8, 9, 10).

So although resistant starches will not yield as many calories as regular carbs during digestion, they may be transformed into SCFA’s that provide calories later.

Therefore, green and yellow bananas may provide similar amounts of calories in the end.

Bottom Line: Unripe bananas contain high amounts of resistant starch. Resistant starch escapes digestion and feeds the friendly bacteria in the gut, which use it to produce short-chain fatty acids.

Bananas Contain Many Other Beneficial Nutrients

Bananas contain good amounts of several vitamins and minerals.

One medium-sized banana contains:

• Fiber: 3.1 grams.

• Vitamin B6: 22 percent of the RDI.

• Vitamin C: 17 percent of the RDI.

• Manganese: 16 percent of the RDI.

• Potassium: 12 percent of the RDI.

• Magnesium: 8 percent of the RDI.

• Folate: 6 percent of the RDI.

• Copper: 5 percent of the RDI.

• Riboflavin (vitamin B2): 5 percent of the RDI.

Bananas are tasty and nutritious. They make an excellent, healthy and low-calorie snack.

Bottom Line: Bananas contain good amounts of fiber, vitamin B6, manganese, vitamin C, copper and potassium.

Take Home Message

Bananas generally contain between 72–135 calories and 19-35 grams of carbs, depending on their size.

An average-sized banana contains about 100 calories and 25 grams of carbs.

Reposted with permission from our media associate Authority Nutrition.