How Many Calories And Protein Are In A Banana? Key Facts

A medium banana has about 105 calories and just over 1 gram of protein. That protein amount is small, but bananas are not eaten for protein. They are eaten for carbohydrates, potassium, and fiber. If you are tracking protein, a banana is not a significant source, but it still fits easily into a balanced diet.

How Many Calories Are in a Banana by Size?

Banana calories depend almost entirely on size. The larger the fruit, the more carbohydrates and calories it contains. The USDA uses a standard medium banana, measuring 7 to 8 inches long, as the reference point.

Here are the standard calorie counts based on size:

• Extra small (under 6 inches): about 72 calories
• Small (6 to 7 inches): about 90 calories
• Medium (7 to 8 inches): about 105 calories
• Large (8 to 9 inches): about 121 calories
• Extra large (over 9 inches): about 135 calories

These figures come from USDA food composition data. Most bananas sold in grocery stores fall into the medium or large category. If you weigh your food, 100 grams of raw banana flesh contains about 89 calories.

How Much Protein Is in a Banana?

A medium banana contains about 1.3 grams of protein. A large banana has roughly 1.5 grams. Even a cup of sliced banana provides only about 1.2 grams.

Bananas are not a meaningful protein source. For comparison, a single large egg provides about 6 grams of protein, which is more than four times the amount in a large banana. Your body needs protein to build and repair muscle, make enzymes, and support immune function. You would need to eat an unrealistic number of bananas to meet daily protein needs this way.

That does not make bananas useless. They provide quick-digesting carbohydrates that help fuel exercise and replenish glycogen stores after a workout. Many athletes eat a banana alongside a protein source like Greek yogurt or a protein shake to get both fuel and recovery nutrients.

What Else Is in a Banana?

Bananas are primarily carbohydrate. A medium banana contains about 27 grams of total carbohydrates, including about 3 grams of fiber and roughly 14 grams of naturally occurring sugar.

The fiber in bananas is worth attention. A medium banana provides about 10 percent of your daily fiber needs. Fiber slows digestion, helps stabilize blood sugar, and supports regular bowel movements. The type of fiber in bananas changes as the fruit ripens. Green bananas are higher in resistant starch, which acts like soluble fiber and feeds beneficial gut bacteria. As bananas ripen and turn yellow, the resistant starch converts to simple sugars.

Bananas are also well known for potassium. A medium banana provides about 422 milligrams of potassium, which is roughly 9 percent of the daily recommended intake for adults. Potassium helps regulate blood pressure, supports nerve signaling, and is important for muscle contractions. Bananas also provide vitamin B6, vitamin C, and magnesium in smaller amounts.

Does Ripeness Change the Calories or Protein?

Ripeness does not change the calorie or protein content in any meaningful way. A green banana and a fully ripe banana of the same weight contain nearly identical calories and protein.

What changes is the form of the carbohydrates. Green bananas contain more resistant starch, which your body does not fully digest. This means a green banana may provide slightly fewer usable calories than a ripe one, though the difference is small. Ripe bananas have more free sugars, which digest faster and raise blood sugar more quickly.

For people with diabetes or those watching blood sugar, this matters. A ripe banana has a higher glycemic index than a green one. The overall glycemic load of a medium banana is still moderate, not high, because the fiber helps blunt the blood sugar response.

How Do Bananas Compare to Other Fruits?

Bananas are higher in calories and carbohydrates than many other fruits. This is not a reason to avoid them, but it is useful context if you are counting calories or carbohydrates.

Here is how a medium banana compares to one cup of other common fruits:

• Banana (medium): 105 calories, 27 grams carbs
• Apple (medium): about 95 calories, 25 grams carbs
• Orange (medium): about 62 calories, 15 grams carbs
• Strawberries (1 cup): about 49 calories, 12 grams carbs
• Blueberries (1 cup): about 84 calories, 21 grams carbs

Bananas offer more potassium than most of these fruits. They are also one of the most affordable and portable fruit options available. If you enjoy bananas, they are a legitimate part of a healthy diet. If you are on a low-carbohydrate diet, you may prefer lower-carb fruits like berries.

Are Bananas Good for Weight Loss or Weight Gain?

Bananas can fit into either a weight loss or weight gain plan. No single food determines weight outcomes. Your total calorie intake across the day matters most.

For weight loss, bananas can be helpful because they are filling relative to their calorie count. The fiber and water content promote satiety. A 105-calorie banana is a reasonable snack that can prevent overeating later. Some research suggests that replacing higher-calorie snacks with fruit like bananas supports weight management, but the evidence for bananas specifically causing weight loss is not strong.

For weight gain, bananas are an efficient way to add calories and carbohydrates. They are easy to eat, digest well, and pair naturally with calorie-dense foods like peanut butter, oats, or full-fat yogurt. A banana with two tablespoons of peanut butter adds roughly 300 calories and about 8 grams of protein to your intake.

Should You Eat Bananas Before or After Exercise?

Bananas are a practical choice around exercise because they provide easily digestible carbohydrates. Eating a banana 30 to 60 minutes before a workout can supply quick energy without causing stomach discomfort.

After exercise, bananas help replenish muscle glycogen, the stored form of carbohydrate your muscles use during activity. Some studies have compared bananas to sports drinks for post-exercise recovery and found them comparable for fueling performance in certain types of exercise. The evidence is not conclusive for all athletic contexts, but bananas are a reasonable whole-food option for general fitness.

For longer endurance sessions lasting over an hour, bananas alone may not provide enough carbohydrates. You would need additional sources of fuel during extended exercise.

Do Bananas Cause Blood Sugar Spikes?

Bananas raise blood sugar, but the effect is moderate for most people. A medium banana has a glycemic index of about 51, which is considered low to medium. The glycemic load is about 13, which is moderate.

Pairing a banana with protein or fat slows digestion and blunts the blood sugar response. Eating a banana alone on an empty stomach produces a faster rise than eating it with yogurt, nuts, or peanut butter. People with diabetes can include bananas in their meal plan, but portion size and ripeness matter. A smaller, less ripe banana is a better choice for blood sugar control than a large, fully ripe one.