Bananas are a beloved fruit enjoyed worldwide, not just for their sweet taste and convenience, but also for their impressive nutritional profile. If you’re watching your calorie intake or simply curious about what’s inside this popular snack, you’re likely asking: How Many Calories Does A Banana Have?
Let’s dive into the details. A medium-sized banana, weighing approximately 100 grams, contains around 89 calories (1). This moderate calorie count makes bananas a great choice for a healthy snack or a nutritious addition to your meals.
But calories are just one piece of the puzzle. Here’s a comprehensive look at the nutrition facts for one medium banana (100g):
- Calories: 89
- Water: 75% – contributing to hydration
- Protein: 1.1 grams – essential for body building and repair
- Carbohydrates: 22.8 grams – the primary energy source
- Sugar: 12.2 grams – natural sugars for quick energy
- Fiber: 2.6 grams – crucial for digestion and satiety
- Fat: 0.3 grams – very low in fat
Carbohydrates: The Energy Powerhouse in Bananas
Bananas are primarily known for being a good source of carbohydrates. The type of carbs in bananas, however, changes significantly as they ripen. In unripe, green bananas, the majority of carbohydrates come in the form of starch. In fact, green bananas can have up to 80% of their dry weight as starch.
As bananas ripen, this starch undergoes a transformation, converting into natural sugars like sucrose, fructose, and glucose (2). By the time a banana reaches full ripeness, the starch content drops dramatically, becoming less than 1% of its composition. Conversely, the sugar content increases, potentially reaching over 16% of the banana’s fresh weight in ripe bananas (2). This is why ripe bananas taste much sweeter than their green counterparts.
Despite their sugar content, bananas have a relatively low glycemic index (GI), ranging from 42 to 58 depending on ripeness (3). The GI measures how quickly the carbohydrates in food raise your blood sugar levels. The lower GI of bananas is attributed to their content of resistant starch and fiber, which slow down sugar absorption.
Fiber: Beneficial for Digestion and Blood Sugar Control
A significant portion of the starch in unripe bananas is resistant starch. This type of starch acts much like fiber, resisting digestion in the small intestine and passing into the large intestine. Here, it becomes a food source for beneficial gut bacteria, which ferment it to produce butyrate, a short-chain fatty acid. Butyrate is known to have positive effects on gut health (4).
Bananas are also a good source of other types of fiber, including pectin. As bananas ripen, the water-soluble pectin content increases. This change in pectin is a key factor in why bananas soften as they mature (5).
Both pectin and resistant starch play a role in moderating blood sugar levels after eating. They help to slow down the digestion and absorption of sugars, preventing rapid spikes in blood glucose.
In Conclusion
While a medium banana contains around 89 calories, it’s packed with valuable nutrients, including fiber, vitamins, and minerals. The carbohydrates in bananas provide energy, and the fiber content contributes to good digestive health and blood sugar management. Whether you prefer them green or ripe, bananas are a healthy and convenient fruit to include in a balanced diet.
