The Unexpected Side Effect Of Eating Green Bananas

Bananas are the perfect portable snack, and they even come in their own biodegradable wrapper. A medium banana gives you 105 calories, 12 grams of natural sugar, and 3 grams of fiber. Bananas are a good source of potassium, providing 12% (for men) or 16% (for women) of your recommended amount. Although bananas can help with a sensitive stomach and firm up your stool, one side effect of bananas can be gas. Bananas contain sorbitol, which is a sugar alcohol that's metabolized much slower, causing more gas, according to Healthline.

You'd think that because green bananas have less sugar, they might make you less flatulent. Not really. Green bananas are classified as dietary fiber because they have more resistant starch. Resistant starch moves through your stomach, where it gets broken down by the bacteria in your large intestine, according to Medical News Today. As a result, you could become gassy as a side effect of eating green bananas.

If you've ever eaten a green banana, you might notice it's much more bitter than a ripe one. Its firm texture makes it difficult to peel. Because about 80% of the weight of a green banana is starch, it's also lower in sugar than a banana (via Healthline). That's why green bananas are much lower on the glycemic index than ripe bananas; it has less of an impact on your blood sugar. What happens during the ripening process of a banana is that the starch turns into simple sugar.

However, eating a green banana means that this starch has to be processed by your body. The resistant starch in a green banana ferments in your gut. As a result, the bacteria in your gut produce carbon dioxide, hydrogen, and methane gas, according to a 2013 study in Advances in Nutrition. Sure, this fermentation might result in uncomfortable bloating, but another byproduct of your body processing resistant starch is short-chain fatty acids (SCFA) such as butyrate. Butyrate helps your immune system and reduces inflammation, according to the Cleveland Clinic.

According to a 2022 study in the Journal of Functional Foods, the resistant starch in foods like green bananas can improve your digestive health by increasing the frequency of your bowel movements. This could factor into your risk of colon cancer. Resistant starch can also affect the diversity of your gut microbiome by increasing the growth of good bacteria. If you're trying to lower your glucose levels, resistant starch is digested more slowly, which means a slower release of glucose into your bloodstream.

The SCFAs produced by your gut by consuming resistant starch could also lower your cholesterol levels. Acetic acid, which is one of those SCFAs, helps your body metabolize cholesterol. A diet rich in resistant starch can also help you manage your weight by increasing the hormones that help you feel full. According to registered dietitian Amy Burkhart, green bananas are also low-FODMAP, which means they might not aggravate people with irritable bowel syndrome.