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What are the worst foods for IBS?

Andrew Bellingham

Andrew Bellingham

Pharmacist | 20+ Years | BPharm | Dip Clin Pharm

Irritable Bowel Syndrome (IBS) is a long-term condition that affects the large intestine, causing symptoms like stomach pain, bloating, wind, diarrhoea, and constipation. These symptoms can vary in intensity and often come and go. IBS is a functional disorder, meaning the symptoms result from changes in how the gut works, rather than any clear physical problems.

The exact cause of IBS isn’t known, but factors like muscle contractions in the gut, issues with the nervous system, severe infections, changes in gut bacteria, and stress early in life may play a role.

Certain foods can trigger symptoms or make them worse, leading to discomfort and disruption in daily life. By avoiding these trigger foods, you can reduce how often and how severe your symptoms are, leading to better overall health and well-being. 

What foods to avoid with IBS

High-FODMAP Foods

FODMAPs (Fermentable Oligo-, Di-, Mono-saccharides and Polyols) are short-chain carbohydrates that are poorly absorbed in the gut. They can cause bloating, gas, and diarrhoea.

Foods high in FODMAPs include:

  • Fruits: Apples, pears, cherries, mangoes, and watermelon
  • Vegetables: Onions, garlic, broccoli, cauliflower, and Brussels sprouts
  • Legumes: Beans, lentils, and chickpeas
  • Dairy: Milk, cheese, yoghurt, and ice cream (especially if lactose intolerant)
  • Grains: Wheat, rye, and barley
  • Sweeteners: Sorbitol, mannitol, xylitol, and high-fructose corn syrup

Fatty Foods

High-fat foods can increase gut motility, leading to diarrhoea.

Common fatty foods to avoid include:

  • Fried foods
  • Fast food
  • Fatty cuts of meat
  • Creamy sauces and gravies

Caffeinated Drinks

Caffeine can stimulate the intestines, causing diarrhoea and discomfort.

It’s best to limit:

  • Coffee
  • Tea
  • Colas and other caffeinated sodas
  • Energy drinks

Carbonated Beverages

These drinks can produce gas and lead to bloating.


  • Fizzy drinks
  • Sparkling water
  • Beer


Alcohol can irritate the gut and worsen IBS symptoms.

It’s wise to reduce or avoid:

  • Beer
  • Wine
  • Spirits
  • Mixed drinks with sugary mixers


While not all people with IBS are gluten intolerant, some find that gluten worsens their symptoms.

Foods containing gluten include:

  • Bread
  • Pasta
  • Cereals
  • Baked goods

Spicy Foods

Spices can irritate the digestive tract and trigger symptoms.

Common culprits include:

  • Hot peppers
  • Chilli powder
  • Curry
  • Mustard

Artificial Sweeteners

Many artificial sweeteners can cause digestive issues.

Common ones to avoid are:

  • Aspartame
  • Sucralose
  • Saccharin

Dairy Products

For those who are lactose intolerant, dairy products can cause bloating, gas, and diarrhoea.

It’s best to avoid or limit:

  • Milk
  • Cheese
  • Ice cream
  • Yoghurt

Insoluble Fibre

While fibre is essential for a healthy diet, insoluble fibre can aggravate IBS symptoms.

Foods high in insoluble fibre include:

  • Whole grains
  • Nuts and seeds
  • Corn bran
  • Vegetables like celery, skin of fruits and tomatoes

Frequently asked questions about irritable bowel syndrome

What are the best foods to avoid with IBS?

Avoid high-FODMAP foods like apples, onions, and wheat. Also, limit dairy, fatty foods, caffeine, and spicy dishes.

Are dairy products bad for IBS?

Dairy products can worsen IBS symptoms for some people, particularly those who are lactose intolerant.

Can spicy foods worsen IBS symptoms?

Yes, spicy foods can worsen IBS symptoms in some people, leading to increased discomfort and digestive issues.

A woman holds her tummy in discomfort caused by IBS

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