Updated: October 2026
In short: With irritable bowel syndrome there is no one-size-fits-all diet, but there is a tried-and-tested path: a food diary shows your personal triggers, regular meals and less stress ease the gut, and soluble fibres such as oats are often better tolerated. The low-FODMAP diet is a time-limited test, ideally with medical or dietitian support. Only a doctor can diagnose irritable bowel syndrome. As of: October 2026.
Abdominal pain, bloating, sometimes diarrhoea, sometimes constipation: many people quickly suspect irritable bowel syndrome. Here you'll learn what diet can do and where it reaches its limits.
What is irritable bowel syndrome actually?
Irritable bowel syndrome (IBS) is a chronic functional disorder of the gut. The NIDDK describes as the most common symptoms abdominal pain, often linked to bowel movements, and changed bowel movements. Bloating, a feeling of incomplete emptying, whitish mucus in the stool, diarrhoea, constipation or an alternation of the two can be added.
The exact cause is unclear. Discussed are disrupted communication between brain and gut, plus stress, infections or food sensitivities. According to the NIDDK, IBS doesn't permanently damage the gut. The NHS calls it usually a lifelong condition in which diet, lifestyle and, where applicable, medication can help.
Important: other causes can produce similar symptoms. Before you settle on "irritable bowel syndrome", get a medical examination.
Which triggers are typical for irritable bowel syndrome?
Typical triggers are alcohol, caffeine, spicy and fatty food, stress and anxiety, and regular antibiotic use. That's what the NHS lists. It also points out that symptoms can occur without an identifiable trigger.
That's why: triggers are individual. What gives your friend symptoms, you may tolerate without a problem. Instead of working through lists from the internet, a systematic look at your own daily life is worthwhile. The NHS also advises not drinking more than three cups of tea, coffee or other caffeinated drinks a day and being cautious with fizzy drinks and alcohol.
How do you keep a food diary for irritable bowel syndrome?
For two to four weeks, note what you eat and which symptoms occur when. The NHS recommends exactly that: a diary of food and symptoms to identify and avoid triggers.
- Time, meal and drinks with amounts
- Symptoms with severity from 1 to 5 and time
- Stool form according to the Bristol scale
- Stress, sleep, exercise, for women also cycle day (the NIDDK mentions stronger symptoms during the period)
Practical tip: always change just one thing at a time. If you cut out wheat, milk and onions at the same time, you won't know afterwards what helped. The diary is also a good basis for discussion with the doctor's practice or nutrition counselling.
What does low FODMAP mean, and who is it useful for?
FODMAPs are short-chain carbohydrates that are poorly absorbed in the small intestine and fermented by bacteria in the large intestine. That can trigger gas, bloating and pain. According to Healthline, mainly people with irritable bowel syndrome benefit; the NIDDK lists the low-FODMAP diet as an option.
It isn't a permanent diet. Typical is about three weeks of cutting out high-FODMAP foods, then reintroducing individual groups to find your triggers. Healthline explicitly recommends medical or dietitian support so you don't go without unnecessarily and stay well nourished. And: these carbohydrates are not harmful for people who tolerate them.
Which foods are high in FODMAPs, which low?
The examples come from the NIDDK and Healthline. The classification of individual foods and portion sizes differs depending on the list, so have the exact selection shown to you by professionals.
| Food group | High FODMAP (reduce on a trial basis at first) | Low FODMAP (usually better tolerated) |
|---|---|---|
| Fruit | Apples, pears, mango, cherries, watermelon | Banana, orange, strawberries |
| Vegetables | Onions, garlic, mushrooms | Carrots, spinach, peppers |
| Grains | Wheat and rye products | Rice, maize, oats, quinoa |
| Milk | Regular dairy products | Hard cheese |
| Legumes | Beans and other legumes | Usually tested only in small amounts |
| Sweets | Honey, sugar alcohols such as sorbitol and xylitol | Sugar in small amounts |
| Protein | Usually unproblematic | Eggs, fish |
Notable: even healthy foods such as apples and onions are on the left. That doesn't mean they're bad. It only means they are among the first suspects when the gut is sensitive. More on gut-friendly eating in general is in Healthy Gut Diet.
How much fibre makes sense with irritable bowel syndrome?
Increase it slowly and favour soluble fibre. The NIDDK recommends eating fibre only 2 to 3 grams per day more so that gas and bloating don't increase. Soluble fibres, such as in beans, fruit and oats, help irritable bowel syndrome better according to the NIDDK.
The NHS names oats, flaxseed, legumes and carrots as soluble sources. With diarrhoea, it advises rather reducing very high-fibre foods such as wholegrain, nuts and seeds. So it depends on whether diarrhoea or constipation predominates for you.
You'll find an overview with amounts in High-Fibre Foods. For hard stool, this helps Constipation: What Helps, for bloating Bloated Belly: What Helps, for thin stool Diarrhoea: What Helps.
What role do stress, exercise and drinking play?
A big one. The NHS advises finding ways to relax and moving a lot. It explicitly names stress as a possible trigger, and the NIDDK describes the interplay of brain and gut as a possible cause. Fixed mealtimes and pauses while eating help; more on this in How Your Gut and Your Mind Are Connected and Reducing Stress.
Also drink enough: the NHS gives at least 8 to 10 drinks, about 1.5 litres a day, for example water or caffeine-free herbal tea. According to the NHS, you can try probiotics for one month. Bring this up at the practice beforehand if you take medication or have pre-existing conditions.
When should you see a doctor with irritable bowel symptoms?
At the latest when symptoms last longer than four weeks, says the NHS. You should have unexplained weight loss, blood in the stool or lumps you can feel in the abdomen checked immediately. A sudden change in your digestion should also be examined.
The doctor rules out other conditions such as coeliac disease or chronic inflammatory bowel disease. Only then is irritable bowel syndrome a sensible diagnosis. You'll find an overview of all topics around digestion in the Gut and Digestion Guide and at Stimulating Digestion.
Pairs well with frank.
A mild tea can become a routine in stressful phases: our Happy Stomach Tea (organic, loose, with fennel, aniseed, chamomile, ginger, linden blossom and sage, from 15 EUR) is a pleasant companion. It doesn't replace a medical check and doesn't treat irritable bowel syndrome.
You might also like
- Which Foods Are Healthy for the Gut - Our Tips for a Healthy Gut Diet
- How Your Gut and Your Mind Are Connected
- Stress Symptoms - 5 Tips for Reducing Stress
Frequently asked questions about irritable bowel syndrome diet
What can I eat with irritable bowel syndrome?
There is no one-size-fits-all list. Often well tolerated are oats, rice, carrots, banana, eggs and fish. Which foods cause you problems is shown by a food diary over two to four weeks.
Do I have to eat low FODMAP with irritable bowel syndrome?
No. Low FODMAP is a time-limited test, usually with about three weeks of cutting out followed by reintroduction. Ideally approach it with a doctor or nutrition counselling so you don't go without unnecessarily.
Is fibre good or bad with irritable bowel syndrome?
Soluble fibres such as in oats are usually better tolerated. According to the NIDDK, increase the amount by only 2 to 3 grams per day. With diarrhoea, it can make sense to briefly reduce very high-fibre food.
Can stress trigger irritable bowel syndrome?
Stress and anxiety are considered typical triggers according to the NHS, and the NIDDK describes disrupted communication between brain and gut as a possible cause. Relaxation and exercise are therefore part of self-help.
How do I know whether it's irritable bowel syndrome?
You can't determine that yourself. Other causes can produce similar symptoms. If they last longer than four weeks, get a medical examination.
Do probiotics help with irritable bowel syndrome?
The NHS suggests trying probiotics for one month. There is no healing promise. If you take medication, are pregnant or have pre-existing conditions, talk to your doctor first.
Note: This article is for general information and does not replace medical or therapeutic advice. If you have symptoms or pre-existing conditions, are pregnant or take medication, please speak to your doctor first.
