Eight foods that will trigger your IBS – and what to have instead

3 months ago 24

By Hattie Garlick

August 7, 2025 — 11.16am

Irritable bowel syndrome may not be a club anyone wants to be part of, but many of us are finding that we’ve been accepted into its ranks without ever applying.

“Irritable bowel syndrome, or IBS, is a common condition which affects the gastrointestinal system,” says Dr Vikram Murthy, a GP and the co-founder of Harley Street clinic Murthy Health. “Symptoms can include constipation, diarrhoea, bloating and stomach cramps, but it may also cause back pain, urinary issues, nausea, flatulence and you may pass mucus too.”

He says the cause remains unknown and there is no cure. “We do know that it has some link to family history, and also that it can be triggered by anxiety, stress and certain foods.”

Irritable Bowel Syndrome affects about 20 per cent of Australians, but there is no known cure.

But all is not lost. In fact, while medicines can help, “diet is the main factor that can control symptoms,” he says. And as a general rule, the foods which fall into the camp known as FODMAPS – short-chain carbohydrates – are the ones to restrict or avoid completely.

Here are eight foods to avoid – and what to have instead.

What is a FODMAP and why does it matter?

“FODMAP is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides and polyols,” says Eve Kalinik,a nutritional therapist and the author of Happy Gut, Happy Mind.

“They’re a group of carbohydrates and sugars that are not completely digested or absorbed in the gut,” she says. Instead, once eaten, they can ferment in your intestines, potentially producing those unpleasant symptoms from bloating to cramping that plague many IBS sufferers.

FODMAPS come in five categories:

Fructose – this is a sugar that makes many fruits problematic.
Polyols – these are sugar alcohols that occur naturally in stone fruits and some vegetables, as well as some processed foods as an additive.
Fructans – it is most commonly consumed via onions, garlic and wheat. It is a fermentable (gas-producing) sugar.
GOS or galactooligosaccharide – these are short-chain carbs that lurk in legumes, including beans, chickpeas, and lentils.
Lactose – this is a sugar found in milk products.

The eight worst foods for IBS

1. Wheat

Gluten gets a bad reputation but it is not always the enemy, suggests Dr Emily Leeming, a nutrition and microbiome scientist and the author of Genius Gut.

“Some people with IBS report feeling better on a gluten-free diet, but this isn’t the case for everyone,” she says.

In fact, if bread worsens your IBS symptoms, its gluten content may be a red herring: “For some wheat-containing foods like bread and pasta – which contain high levels of both gluten and one or more FODMAP – it can seem like gluten is triggering issues, when in fact it’s the FODMAP.”

Studies suggest that for most IBS sufferers who find food containing gluten a trigger, the enemy is actually fructans, a type of sugar in FODMAP foods.

Gluten in bread has long been blamed as the trigger for IBS symptoms but it appears to be a red herring.

2. Dairy

“Dairy can be aggravating for people with IBS because they may struggle to digest lactose, a natural sugar found in milk products,” says Kalinik. But there is hope for dairy lovers.

Fermented milk products like hard cheese or yoghurt may be better tolerated, she suggests.

“This is because during the fermentation process the lactose is mostly negated.” When faced with a cheese board, a portion of self-control is still advised.

“Even with fermented dairy it can be a case of being dose specific to the individual,” says Kalinik.

3. Beans and legumes

Beans and legumes are high in fibre and if you are suffering from dysbiosis, or an imbalanced microbiome, high fibre meals can create gas or discomfort, says Rhian Stephenson, a nutritionist. That’s because they contain another category of FODMAP – galactooligosaccharides or GOS.

These foods aren’t unhealthy, stresses Stephenson. “In fact, they are extremely important for the overall health of our microbiome and our nutrient intake. The problem only arises when we have an imbalance in our gut bacteria.”

Soaking beans and legumes overnight, then rinsing before cooking, makes them easier for some (but not all) IBS sufferers to digest.

4. Alcohol

A third of those with IBS say that alcohol makes their symptoms worse, says Dr Leeming. Some alcohol also contains FODMAPs so if you are sensitive to those, and find alcohol a trigger, Dr Leeming suggests you avoid rum and red wine.

Clear spirits like gin and vodka are lower in FODMAPs but “even a small amount of alcohol can act like an irritant to the gut barrier lining, and can affect how well your gut digests and absorbs nutrients,” she says.

5. Spicy foods

“Spicy foods can act as an irritant to the gut, and many individuals with IBS will already have more irritation or inflammation than those without IBS,” says Stephenson. Again though, don’t throw out the Balti.

“It’s important to look at the type of spicy food you’re eating,” Stephenson stresses. “Takeaways or shop-bought spicy meals may also have added chemicals, flavourings, sugars, and emulsifiers that can exacerbate IBS.” You might find homemade curry less aggravating.

Lovers of curry may find their IBS symptoms triggered when they eat spicy food but homemade versions may be a better option.

6. Deep-fried or fatty foods

Countless surveys have linked fatty and deep-fried foods with IBS symptoms. In one survey, more than half of respondents felt their symptoms are triggered when they eat fatty or fried foods.

“Deep fried foods are difficult to digest,” says Stephenson. “They’re often also ultra-processed, so can be fried in unhealthy, rancid oils, and be accompanied by higher amounts of sugar, preservatives, or emulsifiers, which can add to their potential effects on digestion.” Try grilling or air frying instead.

7. Coffee

Mixed news for those who cannot wake up without a cup. One study showed that those without IBS who drank coffee were 16 per cent less likely to develop the condition than those that didn’t. The opposite applies for those who already have IBS however.

“The caffeine in coffee can stimulate the gut, so food moves faster through your system and that can cause diarrhoea in those with sensitive guts,” says Dr Leeming.

The cause can likely be located deep within your gut microbiome.

“In some of my own research we found that coffee was one of the foods most strongly linked to gut microbiome composition,” says Dr Leeming. Coffee drinkers tend to have higher microbiome diversity.

Still, Dr Leeming adds: “If you have IBS and find caffeine to be a trigger for you, try switching to decaf or herbal tea. Peppermint tea contains menthol, found in higher amounts in peppermint oil capsules, which acts as an antispasmodic, easing sensitivity and pain.” We’ll raise a mug to that.

8. High-FODMAP fruits and vegetables

These include:

Cruciferous vegetables such as broccoli, sprouts, cabbage and cauliflower.
Onions and garlic.
Fruits like apples, cherries and mango.

Most of the time, explains Kalinik, they move through the gut without incident. In fact, they can be a boon “because some of them are rich in prebiotics and they can have a positive impact on the health of our gut microbiome. When they move through the small intestine they naturally attract water and when reaching the large intestine act as a fuel source for our gut microbes”.

While it’s widely considered a healthy choice, high fibre cruciferous vegetables like broccoli can be difficult for IBS sufferers to digest.

For IBS sufferers, however, they can prove problematic.

“People with IBS can have problems with transition time through the gut. Their gut wall can be more sensitive and they may also have some level of ‘dysbiosis’ or imbalance of the gut microbiome,” says Kalinik.

It’s likely a combination of one or more of those factors that makes high-FODMAP foods an aggravating factor, causing symptoms like bloating, diarrhoea or constipation.

9. Sorbitol and xylitol

Sorbitol and xylitol are sugar alcohols, or polyols, found naturally in various plants, but they’re also produced commercially as artificial sweeteners in foods such as sugar-free chewing gum, mints and other low-calorie products. One review of studies found that people with IBS reported symptoms such as flatulence, bloating and abdominal discomfort, even when consuming lower amounts than people without IBS.

10. Cashews and pistachios

Cashews and pistachios are both high in FODMAPs which can trigger IBS symptoms, even in small serving sizes. Stick to macademia nuts, walnuts, peanuts and pecans which are all low-FODMAP.

Can you make high-FODMAP foods easier to digest?

Cooking vegetables makes them easier to digest, but the gold standard dietary intervention for managing IBS symptoms, according to a study published in the journal Gut, is the low-FODMAP diet.

Designed to help IBS sufferers identify the precise foods and FODMAP categories that trigger their symptoms. It involves the following steps:

Eliminate all high-FODMAP foods from your diet.
Slowly reintroduce them, one after the other, while monitoring your body’s reaction and assessing which you can tolerate, and which you cannot.

It is not easy, warns Kalinik: “It’s not to be undertaken without the guidance of a qualified practitioner and not for a long period of time either, as it is these very same foods that help to support the health of the gut.”

The Telegraph, London

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