Is banana low FODMAP? Ripe vs firm explained

Banana is the fruit everyone suggests for an upset stomach. It is soft, gentle and easy to grab. Yet in 2017, Monash University retested bananas after many people with IBS said ripe ones made them uncomfortable. The result changed the advice.

So is banana low FODMAP? It depends on how ripe it is. A firm banana is low FODMAP. A soft, ripe banana is high in fructans. Here is why ripeness matters, how much you can eat and what bananas do for your gut.

Is banana low FODMAP?

A firm banana is low FODMAP, but a ripe banana is high FODMAP. In the Monash retest, firm bananas were low in fructans and ripe bananas were high in fructans. Monash now lists a small serve of ripe banana as about a third of a banana.

Fructans are chains of sugar that your small intestine cannot digest. They are the same FODMAP found in wheat, onion and garlic. In bananas, it is the fructans that change with ripeness.

Serving sizes can be updated after new tests. Please check the Monash app for the latest amounts.

Why do ripe bananas have more FODMAPs?

Ripening and cold storage seem to raise the fructans. Monash points to research showing that banana fructans rise when the fruit is stored and ripened in the cold, a common supermarket practice. Plants also tend to build up fructans when stressed by cold or drought.

A 2015 lab study measured fructans in 7 banana types. The highest, Nendran, held 1,433 mg of fructans per 100 g, about 3.5 ounces. Ripening it at a cool 16°C (61°F) pushed its fructans even higher.

This means two bananas that look alike may not act alike. Variety, storage and ripeness all play a part.

How do I tell a firm banana from a ripe one?

A firm banana feels solid when you press it gently. The skin is yellow, often with a little green at the tips, and has few or no brown spots. The flesh tastes less sweet and a bit starchy.

A ripe banana is soft, very sweet and covered in brown freckles. That is the banana most people put in banana bread.

Try this. Buy bananas that are still a little green and eat them over the next few days, while they are firm. If you love a ripe one, keep it to about a third and pair it with low FODMAP foods.

Why would ripe banana upset a sensitive gut?

Fructans reach your colon undigested, where gut bacteria ferment them and make gas. A 2017 UK trial used MRI scans in 29 people with IBS and 29 healthy people. A fructan drink filled the colon with gas in both groups, but the IBS group felt far worse.

So the issue is a sensitive gut, not too much gas. That is why calming the gut and brain matters as much as the food.

Fructans are also the most common FODMAP trigger. In a 2024 Belgian trial of 117 people with IBS, hidden fructan powder brought symptoms back in 56% of them. If ripe banana bothers you, fructans are the likely reason.

Are bananas good for diarrhoea?

Cooked green banana has helped diarrhoea in trials, though mainly in children. In a 2001 trial in Bangladesh, 62 young boys with long-lasting diarrhoea ate a rice diet with cooked green banana, pectin or rice alone.

By day 3, 55% of the banana group had recovered, compared with 15% on rice alone. A larger 2010 community trial with 2,968 children found that cooked green banana sped up recovery at home too.

These trials were in young children with infections, not adults with IBS. Still, a 2025 review of 12 studies linked green banana to better bowel function. Its resistant starch feeds gut bacteria that make short-chain fatty acids.

If you have IBS with diarrhoea, a firm banana is a gentle, low FODMAP choice. My IBS diarrhoea diet guide lists more foods that settle loose stools.

Are bananas good for your gut?

Yes, for most people they are a kind food for the gut. I strongly believe gut health plays a major role in nearly every health condition. Bananas carry fibre and resistant starch that feed your gut bacteria.

In a 2011 Greek trial, 34 healthy women ate a banana twice a day, drank a banana-flavoured drink or had water, for 60 days. Bifidobacteria, a friendly bacteria, rose only in the banana group, though the rise was not statistically clear. The banana group also reported less bloating than the water group.

A 2022 US trial tested a resistant starch blend made partly from green banana flour. It eased gut symptoms, and higher doses lowered diarrhoea scores. These are small studies, so they hint at benefits rather than prove them.

This matters because a low FODMAP diet can cut friendly bacteria. A 2022 review of 9 trials with 403 people found the diet consistently lowered Bifidobacteria. Keeping firm bananas on your plate is one easy way to feed your gut during the strict phase.

Can you sort gut-friendly foods from triggers? Try the Trigger or Safe game, or grow your plant count in Gut Garden.

Can I eat ripe bananas again?

Many people can. Monash itself says your diet only needs to be as strict as your symptoms require. If ripe bananas never bother you, there is no need to drop them.

Try this. Once your symptoms settle, test ripe banana on its own. On day 1, eat a third of a ripe banana. On day 2, try half. On day 3, try a whole one. Keep the rest of your food low FODMAP and note how you feel. Stop if symptoms return.

My IBS diet guide shows how to plan each test. For the most common fructan trigger in savoury food, read is onion low FODMAP.

Before you change your diet, please see a doctor about any blood in your stool. The same goes for weight loss without trying, even 3 kg (about 7 lb).

Frequently asked questions

Is a ripe banana bad for IBS?

Not for everyone. Ripe bananas are high in fructans, which trigger symptoms in many people with IBS. If you tolerate them, keep enjoying them. If not, stick to about a third of a ripe banana or choose firm ones.

Are green bananas low FODMAP?

Firm bananas tested low FODMAP in the Monash retest. A banana that is mostly yellow with green tips is likely a safe choice. Very green bananas are starchy and hard to eat raw, so many people cook them instead.

Is banana bread low FODMAP?

Usually not. Most banana bread uses very ripe bananas and wheat flour, and both carry fructans. Look for a recipe made with low FODMAP flour, and keep your slice small.

Can bananas cause bloating?

Ripe bananas can, because their fructans ferment in the colon. Firm bananas are much less likely to. In one trial of healthy women, eating bananas daily actually came with less bloating than drinking water.

What I want you to remember

Banana is low FODMAP when it is firm and high FODMAP when it is soft and spotty. The difference is fructans, which build up as bananas ripen. Choose firm bananas during the strict phase, keep ripe ones to about a third, and test your own limit later.

Bananas can feed your gut bacteria too, so there is no need to fear them.

For a calmer gut every day, join my free 30-Day Calm Gut Challenge.