Key points
  • IBS is a common condition, affecting about 30% of Australians.
  • There is no known cause, but potential triggers may include stress, infection and medication.
  • Dietary strategies are effective management tools to improve IBS symptoms.
  • 3 in 4 people see improvements in IBS symptoms within weeks of adopting a low-FODMAP diet.
  • A low-FODMAP diet involves restricting high-FODMAP foods. These are short-chain carbohydrates, which are poorly digested in the colon. A low-FODMAP diet aims to identify your triggers, before reintroducing non-problematic foods.
  • A strict low-FODMAP diet should be followed short-term. Please seek the advice of a dietitian with experience in the low-FODMAP diet to develop a personalised approach for you.
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What is IBS?

Irritable bowel syndrome (IBS) is a condition of the digestive system. It can cause a variety of uncomfortable symptoms.

Symptoms of IBS include:

  • abdominal pain
  • wind
  • constipation and/or diarrhoea
  • bloating.

These symptoms are also common in other bowel conditions. It's important to consult a doctor to rule out other conditions before IBS can be diagnosed.

Up to 30% of Australians suffer from IBS. The condition occurs more often in females. While it can present at any age, it most often occurs before the age of 40.

What causes IBS?

The causes of IBS are often unclear, but many people find it presents after an episode of gastroenteritis, food poisoning, infection, illness or chronic stress.

Food plays a role in symptom induction for many people, but the foods that trigger IBS symptoms will vary for each person.

Symptoms and severity often change over time. Periods of high stress are known to worsen IBS symptoms in some people.

Treatment of IBS

IBS is a chronic condition, requiring long-term management, but symptoms can wax and wane over time and treatment may only be required intermittently.

Various management strategies exist for IBS. These include prescribed and over-the-counter medications, and drug-free approaches.

Gut-directed hypnotherapy is gaining increasing attention for its efficacy in managing IBS symptoms. This is an alternative or complimentary treatment option alongside dietary management.

Often, changes to your diet are all it takes to improve or lessen IBS symptoms. Working with an Accredited Practising Dietitian (APD) can help you identify which foods and food groups are your personal triggers. This allows you to reduce your intake of these triggers, without missing out on key nutrients in your diet.

Diet and IBS

Dietary strategies are very effective in managing the symptoms of IBS. While foods which trigger symptoms are different for everyone, general dietary tips include:

  • eat more high-fibre foods, like fruit and vegetables, legumes and wholegrains. Find out more about fibre
  • eat less gas-producing foods. These include onion, cabbage, brussels sprouts, cauliflower, dried beans and lentils
  • eat fewer foods containing lactose, like milk, ice cream and some yoghurts (for alternatives view our lactose intolerance health advice page)
  • drink less alcohol
  • limit your intake of food and drinks which contain artificial sweeteners. Sweeteners include aspartame, sorbitol and mannitol.

Some people will have an improvement in their IBS symptoms by adopting a high fibre diet and eating more wholegrains and fruit and vegetables. A more specific strategy for addressing IBS is to adopt a low-FODMAP diet for two to six weeks to help identify trigger foods.

Man choosing tomatoes at supermarket

What are FODMAPs?

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. These are types of carbohydrate (sugar), which are not well absorbed in the small intestine.

When these carbohydrates are poorly absorbed they travel to the large intestine. There they attract water into the gut and are fermented by the gut bacteria, creating gas.

The increased water can result in diarrhoea for some people. The gas resulting from fermentation can also lead to symptoms of bloating, constipation, flatulence and pain.

Common high FODMAP foods include garlic, onion, apples, milk, mushrooms, bread and chickpeas.

How can FODMAPs help manage IBS?

Research has proven that following a low FODMAP diet is the most effective way of managing IBS. Three in four people see improvements in their symptoms after adopting a low FODMAP diet.

By reducing your intake of high-FODMAP foods, symptoms of IBS can improve within weeks. We call this a 'low FODMAP diet'.

An Accredited Practising Dietitian (APD) can guide you through a series of food reintroductions. These reintroductions can help work out which FODMAPs and foods are triggering symptoms.

How long do I stay on a low-FODMAP diet?

While a strict low-FODMAP diet can be a diagnostic tool, it's not recommended you stick to it in the long term.

It's important to avoid restricting all high-FODMAP foods if possible, because:

  • many high-FODMAP foods are also high in prebiotics. These feed the healthy bacteria in your gut. Avoiding these long-term can affect the health of your gut microbiome.
  • most people can tolerate at least some of the high-FODMAP food groups.
  • by identifying which foods are triggering symptoms, you can re-introduce groups that aren't a problem for you. You can make informed food choices, and manage symptoms on a daily basis.
  • avoiding unnecessary restrictions helps ensure you're getting the nutrients you need. It increases variety in your diet.
When to see a dietitian
APD Logo

We recommend seeing a dietitian if you:

  • are experiencing regular symptoms of IBS
  • have been diagnosed with IBS and are looking to manage your symptoms
  • want to understand the possible management strategies to control IBS
  • need guidance on trialling a low-FODMAP diet
  • have been following a low-FODMAP diet and are looking to reintroduce foods which don't trigger symptoms
  • have IBS and you don’t believe you have had any relief from a low-FODMAP diet (there may be other dietary factors at play).

Accredited Practising Dietitians (APDs) are university-qualified nutrition experts. They can provide personalised, evidence-based advice.

APDs are Australia's most qualified dietetics professionals.

Find a dietitian

Top tips
  • See your doctor so they can rule out other bowel conditions before diagnosing you with IBS.
  • See a dietitian for personalised advice on managing IBS symptoms using dietary strategies.
  • Consult a dietitian before adopting a low-FODMAP diet. They can help to identify what might be triggering your symptoms. They can also help to make sure you are still getting enough fibre and all the nutrients you need.
This health advice page was peer-reviewed by an Accredited Practising Dietitian (APD) in February 2022.