Are lentils low FODMAP? How to eat them with IBS

More than 1 in 3 people with IBS say beans or lentils upset their gut. In a Swedish study of 197 people with IBS, only dairy was blamed more often among the high FODMAP foods.

So are lentils low FODMAP? Mostly no, but canned lentils can be. Lentils carry FODMAPs called GOS, and canning, draining and rinsing wash a lot of them away. Here is how much to eat, which lentils to choose and why your gut bacteria will thank you.

Are lentils low FODMAP?

Canned lentils are low FODMAP in a small serve, while home-cooked lentils are higher. Monash University lists canned lentils as a green, low FODMAP serve at 1/2 cup.

Lentils are naturally rich in galacto-oligosaccharides, or GOS. Your small intestine cannot break them down. They travel to your colon, where bacteria ferment them and make gas.

Monash advice dates from 2016, and serve sizes can change after new tests. Please check the Monash app for the latest amounts, including for red and green lentils.

Why are canned lentils lower in FODMAPs?

GOS dissolve in water. In canned lentils, some of the GOS leak out into the liquid in the can. When you drain and rinse them, those FODMAPs go down the sink.

A 2018 Monash lab study tested 35 plant foods and several ways of preparing them. Pickling and canning cut FODMAP levels the most.

Monash says lentils boiled at home and drained well also tend to be lower in FODMAPs. Canned lentils are simply the easiest way to get a gentler result every time.

Try this. Tip canned lentils into a sieve, rinse them under cold water for about 30 seconds, then add them to your meal.

Do lentils cause bloating and gas?

Lentils can cause some gas, but often less than people fear. US researchers asked adults in 3 trials to eat 1/2 cup of beans a day for 8 or 12 weeks.

In the first week, fewer than half reported more gas with pinto or baked beans. Only 19% did with black-eyed peas. Even on control foods with no beans, 3 to 11% said they had more gas. The authors concluded that worries about bean gas may be exaggerated.

A 2024 US trial tested lentils directly. For 12 weeks, 38 adults with a large waist ate either lentil meals or meat meals at lunch. The lentil group ate 980 g (about 2.2 lb) of cooked green lentils a week. Gut symptoms stayed none or mild and were no worse than in the meat group.

These people did not have IBS, so a sensitive gut may react more. Still, it suggests lentils are gentler than many people expect.

Can an enzyme help you digest lentils?

Yes, for some people. An enzyme called alpha-galactosidase breaks down GOS before they reach your colon. It is sold over the counter in many countries.

In a 2018 Monash trial, 31 people with IBS ate high GOS foods for 3 days. Of the 21 who were sensitive to GOS, a full dose of the enzyme clearly reduced their overall symptoms and bloating.

It was a small trial, and the enzyme only works on GOS, not on other FODMAPs. Please check with your doctor or pharmacist before you start any supplement.

Why are lentils good for your gut?

The same GOS that cause gas also feed your friendly gut bacteria. I strongly believe gut health plays a major role in nearly every health condition, and lentils are one of the cheapest ways to feed it.

In a 2009 UK trial of 44 people with IBS, a small daily dose of GOS raised levels of bifidobacteria, a helpful gut bacteria. At 3.5 g a day it also eased bloating and wind. It was small and used a supplement, not lentils.

This matters because a strict low FODMAP diet lowers bifidobacteria. A 2022 review of 9 trials with 403 people found this effect again and again. That is why the strict phase should be short and lentils should come back when you can.

A 2026 review adds that lentils carry resistant starch, polyphenols and plant proteins that may help the gut lining. Most of that evidence comes from lab and animal work, so human trials are still needed.

The wider health picture is strong too. In the 2024 trial above, daily lentils lowered LDL cholesterol and blood sugar after meals. A 2025 umbrella review linked eating more legumes with a lower risk of early death. My fibermaxxing guide explains how to raise fibre without upsetting your gut.

How do you add lentils to an IBS diet?

Start small, use canned lentils and build up slowly. Monash suggests enjoying legumes 2 to 3 times a week.

• Start with 2 to 3 tablespoons of rinsed canned lentils and stay below the 1/2 cup serve at first.
• Swap half the mince for lentils in a pasta sauce, chilli or casserole. Monash suggests this swap for bolognese and casseroles.
• Add them to soups and salads, with low FODMAP vegetables such as carrot, spinach and potato.
• Space them out. Eat lentils at one meal, not at every meal, so FODMAPs do not stack up.
• Flavour without onion and garlic. These add fructans on top of the GOS. My guide on whether garlic is low FODMAP shows how to use garlic-infused oil instead.

If you love lentil curries and soups, my guide to low FODMAP vegetarian meals shows how to keep them gentle.

Lentils add fibre, so drink water with them. If coffee is part of your day too, read my guide on coffee and IBS.

Please see a doctor about any blood in your stool or weight loss without trying, such as 3 kg (about 7 lb). Do this before you change your diet.

Frequently asked questions

Are red lentils low FODMAP?

Dried red lentils that you cook at home still contain GOS, so they are likely to be higher in FODMAPs than rinsed canned lentils. Boiling them in plenty of water and draining well may help. Start with a small portion and check the Monash app for the tested serve.

Are lentils good for IBS constipation?

Lentils add fibre, which can help stools move. In IBS, start with small portions of canned lentils and drink plenty of water. My IBS constipation guide covers kiwi and psyllium too.

Can I eat lentils during the strict low FODMAP phase?

Yes, in small amounts. Monash lists 1/2 cup of canned lentils as a low FODMAP serve. Rinse them well and keep other FODMAPs low at the same meal.

Do sprouted lentils have fewer FODMAPs?

The 2018 Monash lab study tested sprouting along with other methods. Canning and pickling lowered FODMAPs the most, so rinsed canned lentils are the safer bet for now.

What I want you to remember

Lentils are high in GOS, but rinsed canned lentils are low FODMAP at 1/2 cup. Start small, build up slowly and keep onion and garlic out of the pot. Your gut bacteria need the fibre lentils give, so bring them back as soon as your gut allows.

For the full picture of what to eat with IBS, read my IBS diet guide. Feed a happy gut in the Feed the Tummy game, and join my free 30-Day Calm Gut Challenge.