Although no studies directly examine the effects of bananas on weight, they’re high in fiber and low in calories. When included as part of a balanced diet, bananas may help support weight loss goals.

People who want to improve their health are often advised to eat more fruits and vegetables.

However, some people worry that high-sugar fruits like bananas can be fattening. Most fruits contain about 90% carbohydrates, which means they’re higher in sugar. Still, fruits are an essential part of a balanced diet because they provide vital nutritional benefits.

This article explores whether bananas will make you gain or lose weight.

Nutrition facts of bananas

Bananas are high in many nutrients and provide many health benefits.

They contain lots of fiber and carbs, as well as some essential vitamins and minerals.

A medium banana contains:

  • Potassium: 9% of the Daily Value (DV)
  • Vitamin B6: 25% of the DV
  • Vitamin C: 11% of the DV
  • Magnesium: 8% of the DV
  • Copper: 10% of the DV
  • Manganese: 14% of the DV
  • Fiber: 3.07 g, or 11% of the DV

All this comes with about 105 calories, 90% of which are from carbs. Most of the carbs in ripe bananas are sugars — sucrose, glucose, and fructose.

On the other hand, bananas are low in both fat and protein.

Bananas also contain a number of beneficial plant compounds and antioxidants, including dopamine and catechin.

Bananas are high in fiber but low in calories

Calorie for calorie, bananas contain a lot of fiber.

One medium banana provides around 11% of your recommended DV, with just 105 calories.

Fiber is important for maintaining regular bowel habits and plays a vital role in digestive health.

Eating large amounts of fiber has even been linked to a reduced risk of heart disease, diverticular disease, and some cancers.

An adequate fiber intake is also linked to reduced body weight.

One study from 2019 measured the food intake of 345 participants for 6 months. The researchers found that an average increase in dietary fiber of 3.7 grams per day was associated with a 1.4 kg greater weight loss over 6 months in adults with overweight or obesity following a calorie-restricted diet.

Scientists believe this may occur because fiber makes you feel full longer, which may help you eat fewer calories in the long term.

The greener the banana, the higher the resistant starch

The type of carbs in a banana depends on how ripe it is.

Unripe green bananas are high in resistant starch, while ripe yellow bananas contain mostly naturally occurring sugars.

Resistant starches are long chains of glucose (starch) that are resistant to digestion. They act like soluble fiber in the body and offer many potential health benefits, including weight loss and reduced blood sugar levels.

Resistant starch can also slow down the absorption of sugar from foods. This keeps your blood sugar levels stable and helps you feel full.

Additionally, resistant starch may increase fat burning.

Bananas have a low glycemic index, but it depends on ripeness

The glycemic index (GI) is a measure of how much foods raise blood sugar levels. If a food scores lower than 55, it’s considered to have a low GI. A score of 56–69 is medium, and 70 or above is high.

Foods that contain a lot of simple sugars are quickly absorbed and have a high GI value since they cause a greater rise in blood sugar levels.

Eating a lot of high-GI foods has been linked to weight gain and an increased risk of obesity, type 2 diabetes, heart disease, and stroke.

Foods with more slowly absorbed carbs have a lower GI and keep your blood sugar levels stable. Since bananas are 90% carbs, they’re sometimes considered a high sugar fruit that could spike your blood sugar.

However, the GI score of bananas is 42–62, depending on ripeness. This means they’re low to medium on the glycemic index.

Ripe bananas have a higher GI than greener bananas. The sugar content increases as the banana matures, which in turn affects your blood sugar levels.

In general, bananas seem to release their sugars slowly.

In one study of people with type 2 diabetes and high cholesterol, adding 9 ounces (250 grams) of banana to participants’ breakfast for 4 weeks significantly reduced their fasting blood sugar and cholesterol levels.

Low-GI foods like bananas may also help you feel full and keep blood sugar levels stable, which may lead to weight loss over time.

Bananas are healthy and nutritious. They’re high in fiber and low in calories.

Most bananas have a low to medium glycemic index and should not cause big spikes in blood sugar levels compared with other high carb foods.

Although there are no studies that directly examine the effects of bananas on weight, bananas have several properties that should make them a weight-loss-friendly food.

If you’re trying to lose weight, there is absolutely nothing wrong with eating bananas as a part of a balanced diet rich in whole foods.