Written by James McIntosh
Reviewed by Sammie Gill
If you have irritable bowel syndrome (IBS), certain foods and ingredients are more likely to trigger your symptoms. Common culprits include wheat, dairy and spicy foods.
Still, what triggers IBS symptoms can vary from person to person. The foods that lead to cramps, bloating or diarrhoea for your neighbour may leave you feeling just fine.
For people with IBS, doctors and dietitians may recommend a low-FODMAP diet. It means eating fewer carbs and sugars that are difficult to digest and absorb.
Below, we describe 10 foods and ingredients that you may want to limit if you have IBS.
We’ll also look at FODMAPs in more detail. And we'll explore foods that may help you manage your IBS symptoms.
Want to learn more about gut health? Sign up for our newsletter here.
1. Wheat
Wheat is in most breads, pastas, breakfast cereals and baked goods.
It can trigger IBS symptoms because it contains a type of FODMAP called fructans, which is especially likely to lead to gut symptoms.
Research suggests that eating less wheat could help ease symptoms for some people with IBS. It may also be a good idea to avoid other sources of fructans, such as barley and rye.
Still, small amounts of wheat, barley and rye may be absolutely fine – you don’t necessarily need to cut them out of your diet.
If you’re easing up on wheat, make sure to replace it with a suitable alternative, like rice, corn, oats, buckwheat or quinoa.
You might opt for wheat-free or gluten-free breads and pastas. If a product is gluten-free, it doesn’t contain wheat, rye, or barley, so it’s likely to be low in FODMAPs. But these foods can be more expensive.
Myths surround the role of wheat gluten in IBS. Gluten and some lesser-known wheat proteins, such as amylase/trypsin inhibitors and wheat germ agglutinin, may trigger IBS symptoms for a small number of people.
But contrary to popular belief, fructans (not gluten) is the main trigger for most people with IBS.
In fact, studies have shown that some people who report a gluten intolerance actually have an intolerance to fructans.
2. Dairy foods
Milk, cheese, yoghurt and other dairy products can trigger IBS symptoms such as cramping and bloating.
All animal milks contain a sugar called lactose, and this is what causes problems for some people with IBS.
It’s important to replace dairy products with plant-based alternatives, such as soy or almond milk. Non-organic versions of these are fortified with important nutrients like calcium.
You can also find lactose-free versions of most dairy products. However, when you’re at the store, keep an eye out for these ingredients:
- fructo-oligosaccharides
- inulin
- oligofructose
They’re carbohydrates that manufacturers sometimes add to foods. They can also cause issues for some people with IBS.
3. Fried, greasy and high-fat foods
Research has linked IBS with diets high in fatty foods. In particular, many people say that greasy, fried foods trigger their symptoms.
Pizza, bacon and other red meats, and processed meats (like sausages and burgers) may also lead to IBS symptoms.
The high amounts of fat could increase your gut activity, and this may be at the root of your symptoms.
So, you might opt for cooking methods such as grilling or air frying, which introduce less fat into the mix. Alternatives like poultry, tofu and tempeh may also be a good idea.
4. Spicy foods
Hot spices are another common IBS trigger. They can lead to symptoms such as stomach pain and heartburn.
Capsaicin is the compound that gives chilli peppers their spice, and it’s also behind their effect on your gut.
It can cause food to move through your gut more quickly, which may lead to IBS symptoms for some people.
Spicy foods, such as some Indian and Mexican dishes, often contain other ingredients that can trigger symptoms. We explore some of these ingredients below.
5. Onion and garlic
This classic duo provides a flavourful foundation for countless dishes. But onions and garlic can trigger IBS symptoms for many people.
Both contain fructans, chains of sugar that are difficult for your body to break down and absorb.
Fructans are a FODMAP. Eating them can lead to greater amounts of water and gas in your intestines, which may result in classic IBS symptoms like bloating and diarrhoea.
Onions and garlic provide a distinctive taste that’s hard to replace. Here are some strategies for getting extra flavour without the fructans:
- Use chives or the green tips of spring onions.
- Cook with an onion- or garlic-infused oil.
- Try asafoetida powder, also called hing powder.
- In oil-based dishes (like stir-fries), use a large piece of onion or garlic, then remove it before serving.
- Get creative with other herbs and spices.
6. Beans and other legumes
Beans, lentils and chickpeas are all types of legume. They’re great sources of protein and fibre, but they’re a common trigger for IBS symptoms.
The problem with these plants is that they contain galacto-oligosaccharides, chains of sugars that are in the same boat as fructans.
If these foods are a problem for you, try soaking and rinsing them before you cook with them. This may help reduce their effect on your gut.
FODMAPs are water-soluble, so some leak into the surrounding liquid of tinned beans, for example. Opting for tinned legumes, and rinsing them, likely means that you'll get fewer FODMAPs.
If you’re on a low-FODMAP diet, you don’t need to be bean-free. You can still have small amounts of most legumes.
Meanwhile, tofu and tempeh are good alternative sources of plant protein.
7. Cruciferous vegetables
The vegetables in this family are often leafy, green and have a strong, bitter flavour. Some examples include broccoli, Brussels sprouts, cabbage and kale.
Cruciferous vegetables contain FODMAPs, so they’re a problem for some people with IBS.
In general, these veg also have a reputation for making you gassy, due to their sulphur-containing plant chemicals.
But cruciferous vegetables contain lots of nutrients that your gut microbes love. Plus, they’re rich in other plant chemicals linked with good health.
For example, researchers have found a link between an increased intake of cruciferous vegetables and a lower risk of gut-related cancers.
So, how to keep them in your diet? Boiling cruciferous vegetables makes them easier for your gut to deal with.
Meanwhile, carrots, bell peppers, aubergine and other low-FODMAP vegetables can be kinder on your gut and less likely to trigger symptoms.
8. ‘Sugar-free’ or ‘low-calorie’ foods
You may have tried sugar-free or low-calorie gums, sweets or drinks, for example. Some of these products contain the artificial sweeteners mannitol, sorbitol or xylitol, which are all FODMAPs.
Mannitol, sorbitol and xylitol belong to a class of sugar alcohols called polyols.
They draw water into your gut, and they’re harder for your body to absorb. Also, your gut microbes can ferment them.
All of this means that these sugar alcohols can trigger IBS symptoms in some people.
Polyols are also naturally present in some fruits, notably stone fruits, like plums, apricots and avocados.
If polyols are triggering symptoms for you, you might opt for regular sugar and maple syrup. But if you’re looking for a lower-calorie option, try artificial sweeteners with names that don’t end in ‘-ol’, like sucralose.
9. Caffeine
Caffeine is in many coffees, teas and fizzy drinks, including energy drinks. It’s also in chocolate, which often contains lactose.
Caffeine can cause your stomach to produce more acid, and it can make food pass more quickly through your gut. Both activities can trigger IBS symptoms for some people.
To replace fizzy drinks, you might try kombucha or sparkling water with some slices of fruit and a dash of juice or cordial.
Luckily, plenty of decaf coffees and teas are available. If you’re looking to replace coffee, you might try black tea, green tea, matcha, mushroom coffee or just hot water with lemon.
Not all of these drinks are caffeine-free, but they contain less caffeine than most cups of coffee.
For a little energy boost, try a healthy snack, a nap or a quick spot of exercise, if you’ve got the time.
10. Alcohol
For some people, alcoholic drinks can trigger IBS symptoms like stomach pain and diarrhoea.
If you drink alcohol often, it can impact how well your gut absorbs nutrients and disrupt how food passes through your digestive system.
Health guidelines in the United Kingdom recommend having no more than 14 units of alcohol a week.
A pint of 4% beer or 175-millilitre glass of wine is each 2 units.
In the short term, alcohol leads to a more permeable (or ‘leaky’) gut, and this can trigger temporary inflammation.
Alcohol also disrupts the way your gut functions. One effect is that it can speed up your gut’s muscle contractions, leading to diarrhoea.
At the same time, alcohol is a diuretic – it increases your need to pee, so you lose fluids faster. This can lead to dehydration, meaning that you might struggle to poop the following day.
If you fancy a drink, some low-FODMAP options are wine, vodka, whiskey and gin.
But keep in mind that some mixers contain artificial sweeteners, honey, high-fructose corn syrup and fruit juice. Each can trigger IBS symptoms
Here are some other strategies:
- opting for lower-strength beers and wines
- choosing smaller sizes, like a bottled beer instead of a pint, or a single instead of a double
- trying a fruity mocktail, kombucha or sparkling water infused with fruit
What are the best foods for IBS?
The best foods for IBS vary from person to person. For instance, wheat may be fine for some, but cause a flare-up of symptoms for others.
If you have IBS, doctors and dietitians may recommend a low-FODMAP diet. ‘FODMAP’ stands for:
- Fermentable foods: We struggle to digest them, so they ferment in our gut.
- Oligosaccharides: Some examples of these sugar chains are fructans and galacto-oligosaccharides.
- Disaccharides: Lactose is a famous example from this group of sugars.
- Monosaccharides: This group of sugars includes fructose.
- And
- Polyols: These sugar alcohols include sorbitol and xylitol, for instance.
Each are components of food that our bodies struggle to break down and absorb.
Some foods are naturally FODMAP-free. Here are some examples:
- certain fruits, like kiwis, pineapples, blueberries and unripe bananas
- certain vegetables, including aubergine, cucumber and tomato
- most nuts and seeds, but not pistachios, cashews or coconuts
- eggs
- tofu
- tempeh
- cooking oils
- fish
- poultry
- meat
Because the best and worst foods for IBS vary so much, you’ll need to experiment a bit to discover what works best for you.
Here are some other dietary tips that can help with IBS:
- Keep a food and symptom diary so you can spot what triggers your symptoms.
- When you have time, cook at home using whole foods and fresh ingredients, so you know exactly what’s going into your meals.
- Make sure you’re getting enough fibre, which can help improve IBS symptoms, like constipation.
- Drink plenty of water.
Learn more about low-FODMAP diets.
How to manage IBS symptoms
Managing IBS isn’t just about tweaking your diet. To help ease your symptoms, it’s important to:
- Get plenty of exercise.
- Ask a pharmacist about over-the-counter medicines for particular symptoms.
- Take steps to reduce stress, which might involve trying relaxation techniques and seeing a therapist.
Probiotic supplements may also help some people with IBS, but speak with a doctor before you try anything new.
Probiotics are live microbes that can offer health benefits.
Learn more about live, friendly bacteria here.
Frequently asked questions
Here are some answers to questions that you might have about specific foods.
Are bananas bad for IBS?
Unripe bananas are a low-FODMAP fruit, so they can be a good idea for people with IBS.
Are baked beans bad for IBS?
Baked beans may trigger symptoms for some people. But if you’re a fan, you may not have to cut them out completely.
Start with a few tablespoons of beans when you want them, and keep track of your symptoms as you slowly increase the amount.
Is pasta bad for IBS?
Some forms of pasta can trigger IBS symptoms for some people. Wheat can cause symptoms, so you might opt for a wheat-free or gluten-free version.
Are eggs bad for IBS?
Eggs are a go if you have IBS. They’re low in FODMAPs and a good source of protein, healthy fats and various nutrients.
Summary
What triggers IBS symptoms varies from person to person, but some foods are more likely to cause issues.
If you’ve got IBS, you may need to experiment and note down how different foods affect you.
If you can tolerate any of the foods we list above, there’s no need to remove them from your diet.
When you’re limiting or cutting out certain foods, you don’t want to miss out on their nutrients, so be sure to find healthy alternatives.
Also, it’s important to note: a low-FODMAP is meant to last 4–6 weeks. After that, you’ll reintroduce foods in a systematic way. A specialist gastroenterology dietitian with training in this diet can help.
If you’re not sure how to replace certain trigger foods, your doctor or a dietitian can suggest healthy alternatives.
To learn more about fibre and other gut health topics, visit Symprove’s Gut Hub.
Sources
Diet in irritable bowel syndrome: What to recommend, not what to forbid to patients! World Journal of Gastroenterology. (2017). Link.
Drink less. (n.d.). Link.
Eating, diet, & nutrition for irritable bowel syndrome. (2017). Link.
Fructan, rather than gluten, induces symptoms in patients with self-reported non-celiac gluten sensitivity. Gastroenterology. (2018). Link.
High intake of cruciferous vegetables reduces the risk of gastrointestinal cancers: Results from observational studies. Critical Reviews in Food Science and Nutrition. (2024). Link.
IBS and the low FODMAP diet. (n.d.). Link.
The dietary management of patients with irritable bowel syndrome: A narrative review of the existing and emerging evidence. Nutrients. (2019). Link.
The role of the FODMAP diet in IBS. Nutrients. (2024). Link.
Western dietary pattern is associated with irritable bowel syndrome in the French NutriNet cohort. Nutrients. (2017). Link.
What is IBS? (2021). Link.