While bananas are high in carbohydrates and sugar, they can certainly be part of a healthy weight loss plan. There are over 100 different types of bananas grown and they are the most popular fresh fruit consumed in the United States, with 13.4 pounds per person eaten annually.¹

The bananas you see in the grocery store most often are Cavendish Bananas.² Besides their pleasing flavor, they are less prone to damage and survive transport better than other varieties.

Bananas are often delivered to the store while they are still green, giving them time to ripen and be sold. Because bananas ripen quickly, most of us probably look for slightly greener bananas when shopping. You probably didn’t realize that eating those sooner rather than later may be an advantage, especially if you are trying to lose weight and keep your blood sugar stable.

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How Bananas Can Help With Weight Loss

Bananas are an excellent source of nutrition. Known for their high potassium content, bananas are also rich in antioxidants and are a good source of health-promoting dietary fiber⁴ and many vitamins and minerals.

1 medium banana contains:⁵

112 calories

1 g protein

29 g carbohydrates

3.28 g fiber

15.4 g sugar

450mg potassium (9.5%)

11 mg Vitamin C (18% DV)

0.46 mg Vitamin B6 (27%DV)

25 mcg folate (6%DV)

If you are a banana lover, you’ve probably found that the riper the banana, the sweeter it is. Green bananas are a bit bitter but they also have more fiber⁶ and a higher level of resistant starch. As a banana ripens, the starch content changes, and the fibers are converted to sugar. Otherwise, there is little nutritional difference between green, ripe, or overripe bananas.  

So, if bananas are high in sugar, how can they help with weight loss? 

<p class="pro-tip"><strong>Learn about </strong><a href=fruits-vegetables-colors>fruit colors and nutritional value</a></p>

Fiber

Yes, bananas are naturally high in carbohydrates, but a lot of their carbohydrates come from fiber. Most Americans don’t get enough dietary fiber and it has a number of health benefits, including weight loss⁴. People who eat more fiber have lower rates of heart disease and diabetes, lower blood pressure and cholesterol levels, and improved digestion. 

The amount of fiber in a banana changes based on how ripe it is. The riper the banana, the higher the sugar content and lower the fiber content.

One recent analysis of unripe green bananas found they had significantly higher fiber content (14g/100g) than ripened bananas (1.1 - 2.3g/100g).⁷ 

The sugar content also changed significantly with ripened bananas showing an increase of 5g of sugar over green bananas.

Why is this important for weight loss? Well, the fiber that is in a green banana is high in resistant starch. Resistant starch stays intact throughout your GI tract and is broken down by bacteria in your large intestine.

<p class="pro-tip"><strong>Learn about </strong><a href=high-fiber-low-carb-foods>the best high-fiber, low-carb foods for blood sugar control</a></p>

Some research has shown resistant starch helps increase feelings of satiety.⁸ It may improve insulin sensitivity, and potentially improve glycemic control. Another area of research is how resistant starch may alter the hormones that regulate your metabolism and energy expenditure.

In one study with banana starch, participants lost about 3 pounds in body weight after 4 weeks by adding a banana starch to a drink.⁹ 

There are a few other ways bananas can be good for weight loss. 

Energy for Exercise

If you work out a lot, you’ve probably heard that bananas are good to eat post-workout to replace energy and potassium.¹⁰

With their carbohydrate content, potassium content, and high antioxidant levels bananas provide energy and help reduce muscle cramps and soreness.¹¹ The antioxidants and phytochemicals found in bananas may help reduce inflammation so you recover more quickly.

<p class="pro-tip"><strong>Read about </strong><a href=protein-before-after-workout>eating protein before or after a workout</a></p>

Blood Sugar Control

Since green bananas are lower in sugar and have a high fiber content it makes sense that they can help with a more stable blood sugar level. 

The resistant starch also helps improve your insulin sensitivity, making your body better able to use insulin to get the sugar into your cells. This helps stabilize your blood sugar levels. 

In one study, energy intake was lower and blood glucose and insulin concentrations checked after a meal were lower after consuming a supplement using banana starch.⁸ 

But the size of the banana still matters - the larger the banana, the higher in sugar and carbs. You can try it yourself with your CGM and see how the banana affects your blood sugar.

Tip: Enjoy a small banana with breakfast. Split it in half and spread some peanut or almond butter over it to add protein and fat and monitor your CGM to see how your blood sugar responds.

<p class="pro-tip"><strong>Learn about </strong><a href=increase-insulin-sensitivity>how to improve insulin sensitivity</a></p>

Why the Ripeness of Bananas Matters for Weight Loss

It all has to do with the amount of resistant starch. While the calorie content of a banana doesn’t change based on ripeness, the number of calories available for your body to digest may decrease. It’s all because the resistant starch stays intact and your body can’t absorb those calories. 

The other benefit of bananas on weight loss is that a less ripe banana is higher in fiber. This helps fill you up, may decrease your appetite, and may help stabilize your blood sugar, all of which can be helpful for weight loss. 

<p class="pro-tip"><strong>Read about </strong><a href=achieve-stable-blood-sugar-levels-with-these-everyday-foods>more everyday foods that stabilize blood sugar</a></p>

Appetite

The resistant starch in the green banana stays intact throughout your GI tract and is broken down by bacteria in your large intestine. Some research has shown higher levels of resistant starch increase feelings of satiety.⁸ 

A recent study used banana flour as part of a soup three times a week. They wanted to see if the resistant starch would affect the hormones that trigger feelings of hunger. The people who had the supplemented soup had lower levels of the appetite-regulating hormone ghrelin released. They also ate about 150 calories less per day than the control group.¹²

Glycemic Index

When it comes to blood glucose control and stabilization, green bananas may be helpful. All the extra fiber and lower sugar content make them a great choice. 

Green bananas are lower on the glycemic index scale than ripe bananas with a value of 30 compared to 51, compared to overripe bananas that are between 52 - 70.¹³ 

However, regular bananas can still be just fine to eat as part of a healthy diet, especially when you consider the glycemic load for individual bananas. A banana is right in the middle on the glycemic load scale, but it depends on the portion size. A small banana is around 11, closer to the low end of the scale. A very large banana can be closer to the high end, falling around 20.

This is something you may want to experiment with if you aren’t a fan of an underripe banana. Does the portion size make a difference in your blood sugar response? Monitor your CGM to see how a regular or slightly ripe banana affects your blood sugar and what size works best for you.

<p class="pro-tip"><strong>Read about </strong><a href=low-glycemic-plan>our 7-day low-glycemic diet plan</a></p>

How Many Bananas Can You Eat in a Day if You Want to Lose Weight?

Just like anything else, moderation is the key — there can definitely be “too much of a good thing.” So eating one banana a day, or a few times a week is probably a good place to start. 

While bananas are a great source of nutrition, balancing them with other types of low glycemic fruits is an excellent way to reach all your nutrition goals. A study in PLOS Medicine found that increasing overall fruit intake, including bananas, resulted in a decrease in weight over time. The authors attributed the weight loss to increased feelings of satiety and reduced calorie intake.¹⁴  

Tip: A great way to enjoy bananas and other fruits are to make “nice cream.”  Whip up greener bananas with berries, cherries, or mangos until they are smooth. Freeze the mixture and then scoop it out like ice cream. Top it with chopped nuts or a drizzle of thinned nut butter for a cool summer treat.

Are There Any Issues with Eating Bananas?

Bananas can be included in most healthy eating plans and are a good choice for most weight loss programs, but there are a few things to keep in mind. 

Bananas contain a protein that may cause an allergic reaction in some people. If you are allergic to latex, bananas along with avocados, peaches, and kiwi contain a protein that is similar in structure to the one that causes natural latex allergies.¹⁵

As we talked about, bananas, especially green or partially ripened bananas, are high in fiber and some people experience gas and bloating after eating them. Unripe bananas can also be pretty bitter.

Tip: If you aren’t a fan of the taste of green bananas, try mixing them into a smoothie or oatmeal. You could also try adding green banana flour to a smoothie or shake to get the benefits of the resistant starch without the bitter flavor.   

Do Bananas Contribute to Belly Fat?

It all comes back to that resistant starch content, which stays intact as it travels through your intestines. Resistant starch acts as a prebiotic, feeding the healthy bacteria in your digestive tract.

Because resistant starch doesn’t get broken down into sugar, those calories aren’t used for energy. Some research has suggested that resistant starch also increases energy expenditure and fat oxidation.¹⁶ But as far as belly fat goes, the good news is that eating foods high in resistant starch is associated with reduced abdominal fat.

<p class="pro-tip"><strong>Read about </strong><a href=prebiotic-foods-list>the best prebiotic foods for gut health</a></p>

What's the Best Time of day to Eat Bananas for Weight Loss?

Bananas are a good option at any time of the day. But, since they do contain fiber, they can help fill you up so eating them in the morning with breakfast may help keep you full longer and help cut down on unplanned snacking. 

You can eat bananas at night, just keep in mind that if you aren’t used to eating a lot of fiber, they may cause some gas and bloating which may be uncomfortable and interrupt your sleep.

So, the bottom line is that bananas can be a great part of a weight-loss routine. Keep in mind the portion sizes and opt for a smaller banana and eat it with other foods. 

Raw green bananas tend to be bitter and high in tannins so a lot of people have trouble working them into their diet. But there are other ways of taking advantage of their benefits. There are a variety of green banana products available, including banana flour and supplements.

Give less-ripe bananas or green banana flour a try, and experiment with your CGM to see how they affect your blood sugar.

<p class="pro-tip"><strong>Don't have a CGM?</strong>Learn more about how Signos uses AI and a CGM to help you on your journey towards optimal health.</p>