Is Banana Fast Digesting Carbs? (A Dietitian Answers)

A banana is a source of fast-digesting carbs since it is made up of simple sugars, which are easily digested and absorbed.

However, ripe bananas in particular digest more quickly than unripe bananas since they have fewer complex carbs (such as resistant starch), thus leading to faster digestion.

Learning when to eat bananas, when to pair them with other foods, and how ripe they should be is important for improving your energy levels and balancing your blood sugar.

Key Takeaways

• The ripeness stage of a banana determines the digestion rate because of changes in nutrient characteristics during ripening.

• Ripe and overripe bananas are made up of more simple carbs and thus have a higher glycemic index (GI). Underripe bananas are made up of more complex carbs and have a lower GI.
   
• Bananas can be used as a quick energy source when eaten alone, or paired with protein and/or fat sources to provide more stable energy over time. 

Understanding the Glycemic Index

The glycemic index (GI) is a way of measuring how quickly carbohydrates raise blood sugar levels. The index ranks foods on a scale from 0 to 100, with higher numbers indicating that the food causes a rapid increase in blood sugar levels.

Foods with a high GI (70+) are digested and absorbed more quickly because they contain mostly simple sugars and/or refined carbs which are easier for the body to break down.

Foods with a medium to low GI (low is 1-55 and medium is 56-69) are digested and absorbed more slowly, leading to a more gradual increase in blood sugar levels. This is because they contain more fiber, starch, and fewer simple sugars that take longer for the body to break down.

While the glycemic index is a useful tool when it comes to choosing the right foods for keeping blood sugar levels balanced, it is not the only factor to consider when making food choices. 

The number of carbs in a food and the presence of other nutrients (such as fiber, protein, and fat) can also affect how quickly carbohydrates are digested and absorbed.

• Related article: What Are Fast Digesting Foods?

How Long Does It Take Banana To Digest?

It can take around 30 to 60 minutes for a banana to digest, depending on the ripeness of the banana and how it’s consumed (alone or with food).

If you eat a ripe banana, it will be digested faster than if you eat an unripe banana (more on this later). 

If you eat a banana with other foods, it will be digested slower than if you eat it alone (especially if eaten with protein or fats)

For example, if you have a banana with peanut butter and oatmeal, it needs to be broken down along with the other foods. The oatmeal wouldn’t take too long to break down, but the peanut butter would because fats take longer to digest.

Key points:

• If you want to balance your blood sugars then you should choose unripened bananas and pair them with protein and/or fat sources.

• If you want a faster rise in blood sugar for a quick burst of energy, then have a ripe banana by itself.

Is Banana A Complex or Simple Carb?

Bananas contain both simple and complex carbs because they contain sugar and starch. For this reason, it can be difficult to classify them as complex or simple carbs.

Simple carbs are made up of simple sugar molecules, are low in fiber, and can often be high in refined starch. This makes them easy to digest and faster to absorb, which means they convert to energy more quickly.

Some examples of simple carbs are french baguette, instant flavored oats, watermelon, honey, and soda.

Complex carbs are larger molecules, high in resistant starch and fiber, and low in simple sugars. These characteristics make complex carbs slower to digest and absorb, which means it will take longer to convert them to energy.

Some examples of complex carbs include barley, steel-cut oats, beans, all bran cereal, and wholegrain bread.

So, how does a banana compare to other types of carbs?

The following table shows a few different types of carb foods with their GI score, according to the International tables of glycemic index values. 

*Remember that low GI foods are 1-55, medium GI foods are 56-69, and high GI foods are 70+.

To put this in context, a ripe/overripe banana is slower digesting than white bread and flavored instant oats, but faster digesting than oat bran bread.

It is also faster digesting than all bran cereal, but slower digesting than watermelon.

Related articles:

• Is Bread a Fast or Slow Digesting Carb?
• Is Oatmeal Fast Or Slow Digesting?
• Is An Apple A Fast Digesting Carb?

Ripeness of Bananas: How It Affects Their Digestion Rate

Bananas can have different GI ratings depending on their ripeness, which means the digestion rate will be different as well.

According to the International tables of glycemic index values, bananas can have a low to high GI rating, with under-ripe bananas at 31-42, and ripe and over-ripe bananas at 53-75. One banana variety from Nigeria has been found to have an even higher GI at 75.

The following table shows the GI rating of bananas at different levels of ripeness.

To put it simply, this means that because the carb composition of a banana changes during ripening, the digestion time of a banana also changes. 

“Dietary fiber, sugar, and starch content of bananas cannot be generalized across ripeness stages, and food composition databases typically do not distinguish between bananas at different stages of edible ripeness”

– Katherine M. Phillips, Plos One Journal

Key points:

• A ripe banana can take less time to digest than an unripe banana, as it contains more sugar and less resistant starch and fiber. 

• An unripe banana can take longer to digest because it contains more resistant starch and fiber, and a bit less sugar than a ripe banana.

Benefits of Eating A Fast Digesting Carb Like Banana

Provides Quick Energy

Bananas, particularly ripe bananas, can provide you with energy more quickly which is ideal before and during exercise when your body needs energy to perform optimally.

Having a banana post-workout can also be beneficial because fast-digesting carbs can help replenish energy stores after exercise, allowing for better recovery from exercise

Is Rich In Nutrients

Fast-digesting fruits, like ripe bananas, are a great source of nutrients, which are important for your overall health. Bananas are rich in potassium, magnesium, and vitamin B6. 

Additionally, sugars in whole foods are naturally occurring so they do not add up to your daily added sugar intake.

Can Help With Bulking

Although bananas aren’t particularly high in calories (~120 calories in a large banana), they can help when you’re bulking because they digest quickly and won’t fill you up.

Therefore, including bananas when you’re bulking can help you reach your calorie target without feeling too full. 

Bananas could also help improve your performance in the gym by boosting your energy levels, which could encourage muscle gain.

Drawbacks of Eating A Fast Digesting Carb Like Banana

Won’t Keep You Satiated

Bananas will not keep you full for long, because they’re low in resistant starch and fiber.

This means that it does not provide the same level of satiety as slower-digesting carbs, which can be an issue if you are trying to lose weight because it can cause you to eat more calories than you would if you had eaten a more complex carb.

Spikes Blood Sugar

Bananas, particularly ripe bananas, cause large spikes in blood sugar, which can become a problem over time if you’re consistently eating these types of carbs in addition to processed sugars (i.e. cake, cookies, candy).

Consuming too many high-GI foods can increase the risk of developing insulin resistance (when your body struggles to pull sugar from the blood to use as energy).

If you’re diabetic, having fast-digesting carbs is also not ideal as it can lead to uncontrolled blood sugar levels. 

Energy Provided Is Short-Lived

While eating foods like bananas can provide quick energy, the energy won’t last very long (if it’s not paired) so you may experience a crash in energy shortly after eating, which can leave you feeling tired and lethargic.

When Should You Eat Bananas?

Bananas are ideal before, during, or after exercise:

• Eating a banana 30-60 minutes before a workout can be a good time to get a source of quick energy.

• If your workouts last longer than 60-90 minutes, you could also consider eating a banana during your workout to keep you energized.

• After a workout, a banana can help to replenish energy stores and promote recovery. 

Bananas can also be beneficial to consume in the following situations:

• If you know you won’t be able to eat for a while, having a banana can help prevent low blood sugar levels. However, it should be paired with a fat and/or protein to hold you over for longer.

• Eating a banana in between meals can help keep hunger at bay and having it with you can help you avoid reaching for foods that may not be as healthy.

• Eating a banana before bed may improve sleep, as it is rich in sleep-promoting nutrients like magnesium and tryptophan. If you also pair it with a protein source (i.e. greek yogurt), it can slow down digestion and promote steady blood sugars overnight.

How To Make Bananas Digest Faster or Slower

1. Pair Them With Other Foods

Pairing bananas with other foods slows down their rate of digestion. Pairing bananas with other carbs (i.e. oatmeal) will slightly slow digestion, but pairing them with protein or fats (i.e. nuts, seeds, greek yogurt) will dramatically slow their digestion.

2. Choose Them According To Their Level Of Ripeness

If you choose under-ripe bananas (ones that are more green and firm), it can help slow digestion as the sugar content will be slightly lower, and resistant starch and fiber will be higher.

If you choose ripe or overripe bananas (ones that are more yellow and squishy) it can increase the rate of digestion because the sugar content will be higher, and the fiber and resistant starch content will be lower.

3. Cook Or Mash Them

Cooking bananas can break down some of the fibers and make them easier and faster to digest. If you want a faster-digesting banana then consider baking or grilling it.

Mashing bananas can also make them easier to chew and thus can be digested more quickly than whole bananas.

References

Miller K. C. (2012). Plasma potassium concentration and content changes after banana ingestion in exercised men. Journal of athletic training, 47(6), 648–654. https://doi.org/10.4085/1062-6050-47.6.05

Edo A, Eregie A, Adediran O, Ohwovoriole A, Ebengho S. Postprandial glucose response to selected tropical fruits in normal glucose-tolerant Nigerians. Niger J Clin Pract. 2011 Jan-Mar;14(1):79-82. doi: 10.4103/1119-3077.79270. PMID: 21493998.

Phillips, K. M., McGinty, R. C., Couture, G., Pehrsson, P. R., McKillop, K., & Fukagawa, N. K. (2021). Dietary fiber, starch, and sugars in bananas at different stages of ripeness in the retail market. PloS one, 16(7), e0253366. https://doi.org/10.1371/journal.pone.0253366

Nieman, D. C., Gillitt, N. D., Henson, D. A., Sha, W., Shanely, R. A., Knab, A. M., Cialdella-Kam, L., & Jin, F. (2012). Bananas as an energy source during exercise: a metabolomics approach. PloS one, 7(5), e37479. https://doi.org/10.1371/journal.pone.0037479

Cao, Y., Zhen, S., Taylor, A. W., Appleton, S., Atlantis, E., & Shi, Z. (2018). Magnesium Intake and Sleep Disorder Symptoms: Findings from the Jiangsu Nutrition Study of Chinese Adults at Five-Year Follow-Up. Nutrients, 10(10), 1354. https://doi.org/10.3390/nu10101354

Binks, H., E Vincent, G., Gupta, C., Irwin, C., & Khalesi, S. (2020). Effects of Diet on Sleep: A Narrative Review. Nutrients, 12(4), 936. https://doi.org/10.3390/nu12040936