Irritable bowel syndrome: 20 foods to avoid

Irritable bowel syndrome (IBS) is a common gut disorder whose symptoms — bloating, gas, cramping, diarrhoea, and constipation — are often shaped by what we eat. A major cause is a group of poorly absorbed, fermentable carbohydrates called FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols). When these reach the large intestine, gut bacteria ferment them, drawing in water and producing gas that can trigger symptoms. The foods below are among the most common high-FODMAP or gut-irritating offenders.

Alliums and certain vegetables

1.  Onions — high in fructans, one of the most common IBS triggers, even in small amounts and when cooked.

2.  Garlic — also rich in fructans; a garlic-infused oil can add flavour without the FODMAPs.

3.  Cauliflower — contains polyols (mannitol) that commonly cause gas and bloating.

4.  Mushrooms — high in mannitol, a fermentable sugar alcohol.

5.  Asparagus — high in both fructans and excess fructose.

6.  Broccoli (in large servings) — fine in small portions for many, but larger amounts stack up fructans.

Certain fruits

7.  Apples — high in excess fructose and sorbitol — a classic bloating trigger.

8.  Pears — similar to apples, rich in fructose and sorbitol.

9.  Mango — high in excess fructose.

10.  Watermelon — combines fructose, fructans and polyols.

11.  Stone fruits (cherries, peaches, plums, apricots) — high in polyols such as sorbitol.
Legumes and pulses

12.  Beans, lentils and chickpeas — high in GOS (galacto-oligosaccharides); rinsing canned pulses well can reduce, but not remove, the load.

Dairy and lactose

13.  Cow’s, goat’s and sheep’s milk — high in lactose; lactose-free or plant-based milks (almond, soy, coconut) are gentler.

14.  Soft cheeses, yogurt and ice cream — lactose-heavy dairy that can worsen symptoms; hard, aged cheeses are usually lower.

Wheat and rye

15.  Wheat bread and pasta — high in fructans; sourdough and gluten-free options are often better tolerated.

16.  Rye — another fructan-rich grain found in breads and crackers.

Sweeteners

17.  Honey — high in excess fructose.

18.  High-fructose corn syrup and agave — concentrated fructose found in many processed foods and drinks.

19.  Sugar-free sweeteners (sorbitol, mannitol, xylitol) — polyols in ‘sugar-free’ gum, sweets and diet products that ferment quickly, often within hours.

Other common triggers

20.  Caffeine (coffee and strong tea) — not a FODMAP, but a gut stimulant that can worsen cramping and diarrhoea.

Beyond FODMAPs, several other things commonly aggravate IBS and are worth watching: alcohol, fizzy or carbonated drinks, very fatty or fried foods, spicy dishes, and ultra-processed foods. Large meals can also be harder on a sensitive gut than smaller, more frequent ones.

How to use this list

Rather than cutting everything at once and staying that way, most experts recommend a structured approach: remove suspected high-FODMAP foods for a few weeks, then reintroduce them one at a time while keeping a food-and-symptom diary to see which ones genuinely bother you. Because the strictest phase can make it harder to get balanced nutrition, it’s best done with support from a doctor or registered dietitian — especially if symptoms are severe, persistent, or accompanied by weight loss, bleeding, or other warning signs, which should always be checked by a professional.

General information grounded in guidance from Johns Hopkins Medicine, Houston Methodist, and Monash University’s low-FODMAP research. Not a substitute for personalised medical or dietary advice.