Are Green Bananas High in Sugar? What You Need to Know

October 13, 2025 •

3 min read

According to Healthline, unripe green bananas are mostly starch, which makes up 70–80% of their dry weight. This composition means green bananas are not high in sugar, as much of their carbohydrate content is resistant starch, which behaves very differently in the body than simple sugars.

Quick Summary

This article explains why green bananas contain less sugar than their ripe, yellow counterparts. It covers the science behind resistant starch and its impact on blood sugar, digestion, and overall health. A comparison table highlights the nutritional differences based on ripeness.

Key Points

Low in Sugar: Green bananas contain significantly less sugar than ripe bananas, as their carbohydrates are primarily resistant starch.
High in Resistant Starch: The high resistant starch content in green bananas acts like fiber, slowing digestion and preventing blood sugar spikes.
Improves Gut Health: Resistant starch ferments in the large intestine, feeding beneficial gut bacteria and promoting the production of healthy short-chain fatty acids.
Aids Blood Sugar Control: With a lower glycemic index, green bananas are a better choice for managing blood glucose levels compared to sweeter, ripe bananas.
Supports Weight Management: The fiber and resistant starch promote feelings of fullness, which can help with appetite control and weight loss efforts.
Nutritional Changes with Ripeness: As a banana ripens, its resistant starch converts into simple sugars, increasing its sweetness and glycemic index.

The Science of Green Bananas and Resistant Starch

Unlike their soft, yellow counterparts, green bananas are not high in sugar. The primary reason for this lies in their carbohydrate composition. A significant portion of a green banana's carbohydrates is resistant starch, a form of starch that resists digestion in the small intestine. This means that instead of being rapidly absorbed and converted into sugar, this starch travels to the large intestine, where it is fermented by beneficial gut bacteria. This process is what makes green bananas a powerhouse for digestive and metabolic health.

How Resistant Starch Benefits the Body

The fermentation of resistant starch in the large intestine produces short-chain fatty acids (SCFAs), such as butyrate. These SCFAs are crucial for several aspects of health:

Improved Gut Health: SCFAs provide fuel for the cells lining the colon, helping to maintain a healthy gut barrier. This can lead to reduced inflammation and a more balanced gut microbiome.
Better Blood Sugar Control: Because resistant starch is digested slowly, it prevents the sharp spikes in blood sugar that can occur after eating sugary foods. This is particularly beneficial for individuals with diabetes or those looking to manage their blood glucose levels effectively.
Increased Satiety: The high fiber content and slow digestion rate of green bananas promote a feeling of fullness. This can help reduce overall calorie intake and support weight management goals.

The Ripening Process: Starch to Sugar

As a banana ripens and turns from green to yellow and then brown, a natural process causes the resistant starch to convert into simple sugars like sucrose, glucose, and fructose. This is why a ripe banana tastes much sweeter and has a softer texture. The concentration of sugar increases significantly as the starch decreases. While both green and yellow bananas are nutritious, their effects on blood sugar levels are markedly different. A fully ripe banana has a higher glycemic index (GI) than a green one, meaning it causes a faster rise in blood sugar.

Comparing Green vs. Ripe Bananas

To better understand the differences, here is a comparison table outlining the key nutritional changes that occur during ripening:


Feature	Green (Unripe) Banana	Ripe (Yellow) Banana
Primary Carbohydrate	Resistant Starch	Simple Sugars (Sucrose, Fructose, Glucose)
Sugar Content	Low	High
Taste	Less sweet, sometimes bitter	Very sweet
Texture	Firm, waxy, and starchy	Soft and mushy
Digestibility	Slower to digest; acts like fiber	Easier and quicker to digest
Glycemic Index (GI)	Lower (~30)	Higher (~60)
Key Health Benefit	Gut health, blood sugar control	Easily digestible energy, higher antioxidants

Practical Ways to Incorporate Green Bananas

Since green bananas are firm and not very sweet, they are often cooked rather than eaten raw, much like a vegetable or plantain. Here are a few ways to add them to your diet:

As a Starchy Vegetable: Green bananas can be boiled, fried, or baked and used as a potato substitute in savory dishes. Popular in Caribbean and Latin American cuisines, they are often used in stews or mashed dishes.
Green Banana Flour: This gluten-free flour is made from dehydrated green bananas and is a great source of resistant starch. It can be used in baking or as a thickening agent for sauces and smoothies.
In Smoothies: For a convenient and raw option, some people add grated green banana to their smoothies. While the texture is different, it provides the benefits of resistant starch.

Potential Side Effects

While generally healthy, the high resistant starch content of green bananas can cause some digestive discomfort in certain individuals. Side effects may include gas, bloating, or constipation as the gut adjusts to the increased fiber. It is best to introduce them gradually into your diet to avoid these issues. People with latex allergies should also be cautious, as some bananas contain similar proteins that can cause reactions.

Conclusion: The Final Word on Sugar

In conclusion, green bananas are definitively not high in sugar. Their nutritional profile is dominated by resistant starch, which behaves more like fiber and offers a variety of health benefits, especially for gut health and blood sugar management. While this resistant starch converts to simple sugars as the banana ripens, understanding this transformation allows you to choose the right banana for your dietary needs. By incorporating them correctly, you can leverage the unique benefits that green bananas offer.

For more detailed information on resistant starch and its health benefits, you can consult resources like Healthline's guide on green bananas.

Frequently Asked Questions

As a banana ripens, its natural resistant starch is converted into simple sugars like glucose, fructose, and sucrose. In its green, unripe state, this conversion has not yet occurred, resulting in much lower sugar content.

Resistant starch is a type of carbohydrate that is not digested in the small intestine but is fermented by gut bacteria in the large intestine. It acts like fiber and can improve gut health, enhance insulin sensitivity, and help regulate blood sugar levels.

Both have different health benefits. Green bananas are particularly good for gut health and blood sugar control due to their resistant starch. Ripe bananas offer more antioxidants and are easier to digest for a quicker energy source.

Yes, green bananas can be a good option for people with diabetes. Their lower sugar content and resistant starch mean they cause a slower and less significant rise in blood sugar compared to ripe bananas.

For some people, the high resistant starch and fiber content in green bananas can lead to temporary digestive discomfort, such as gas, bloating, or constipation. It is recommended to eat them in moderation initially.

Green bananas are often cooked rather than eaten raw due to their starchy texture and bitter taste. They can be boiled, fried, or baked and used in savory dishes like curries or mashed plantain-style recipes.

Green banana flour is a gluten-free alternative to wheat flour that is high in resistant starch. It can be used in baking for bread and pancakes or as a thickening agent in sauces and smoothies.