Low FODMAP Diet: What is it and how does it work?

Key Points

• Researchers developed the low FODMAP diet to help IBS sufferers reduce their symptoms.
• A low FODMAP diet includes a variety of foods, including dark chocolate and green kiwi fruit.
• You should always see a healthcare professional before starting a low FODMAP diet to understand the benefits of the diet for your situation.

If you’ve heard about the low FODMAP diet and wondered if it’s something you should try, it’s important to have the right information before you dive in. After all, being informed is being empowered – particularly when it comes to your health and diet.

We’ve compiled this guide to the low FODMAP diet to help you understand what it is, how it works and if it’s right for you. 

What is the low FODMAP diet?

The low FODMAP diet is a homegrown discovery, thanks to researchers at Monash University. They discovered five short-chain carbohydrates or sugars that can be problematic for digestion in some individuals.

Each of these five sugars is represented by a different letter in the acronym FODMAP. That is ‘fermentable’, ‘oligosaccharides’, ‘disaccharides’, ‘monosaccharides' and ‘polyols’.

The Monash University researchers looked at a variety of foods and measured their FODMAP content. They also researched how FODMAPs trigger medically diagnosed Irritable Bowel Syndrome (IBS) symptoms. 

They used this research to develop the low FODMAP diet.

The diet aims to help IBS sufferers avoid foods high in the FODMAPs that trigger their symptoms. Research has found that many IBS sufferers who follow the low FODMAP diet see an improved quality of life.

How does a low FODMAP diet work?

The low FODMAP diet consists of three steps:

1. Remove high FODMAP foods from the diet and replace them with low FODMAP alternatives. This initial phase lasts for between two to six weeks.
2. Reintroduce one type of FODMAP at a time (that is, one of the five sugars that make up the acronym), one food at a time. Each FODMAP and food is reintroduced over a period of three days, with this phase lasting anywhere from two to three months. During this phase, you track which FODMAPs trigger your symptoms. 
3. Continue with a customised approach that considers your tolerance to different FODMAPs and foods.

It’s surprising what you can eat on a low FODMAP diet

While it may sound restrictive, you can enjoy a wide variety of foods on a low FODMAP diet. You may even be surprised at which foods are low FODMAP.

Foods that are low FODMAP

The below list contains some examples of low FODMAP foods:

• Green kiwi fruit
• Eggs
• Plain rice cakes
• Dark chocolate
• Pumpkin seeds
• Camembert cheese
• Eggplant
• Zucchini
• Pineapple
• Almond or soy milk
• Corn flakes

*Remember, foods contain FODMAPs in various amounts so serving size is important.

Foods that are high FODMAP

Below you’ll find examples of high FODMAP foods:

• Cow’s milk
• Apples
• Honey
• Cashew nuts
• Cauliflower
• Mango
• Sugar-free confectionery
• Mushrooms
• Watermelon
• Onion

What can you eat on a low FODMAP diet?

The food you eat on a low FODMAP diet can be diverse and colourful. It’s about finding the low FODMAP foods you enjoy and incorporating them into your meals.

Your low FODMAP day on a plate may look something like this:

• Breakfast – Oats cooked with almond milk, sweetened with maple syrup and sprinkled with walnuts.
• Lunch – Smashed avocado and feta on sourdough spelt bread with a boiled egg.
• Dinner – A tofu stir fry with bok choy, green capsicum and zucchini served with rice.
• Snacks – A few pieces of dark chocolate or a fruit salad made with green kiwi fruit, mandarin, orange and pineapple.

How to follow a low FODMAP diet

If you’re following a low FODMAP diet, start by familiarising yourself with the list of low FODMAP food alternatives. Check if your favourite foods are on the list. If they’re not on the list, find alternatives that you can eat instead.

Then, when grocery shopping, keep your low FODMAP food list handy. Or, better still, write a low FODMAP grocery list and shop from that.

Meal planning can also help you stay organised and eliminate the stress of worrying about what you’re going to eat. Sit down once a week and plan your low FODMAP meals for the week. That will also make your grocery shopping much easier. 

Are there benefits to a low FODMAP diet?

According to Monash University, three in four people who follow a low FODMAP diet see an improvement in their IBS symptoms. This improvement includes a reduction in bloating, discomfort, diarrhea and constipation. 

This is consistent with other research that has found that low FODMAP eating may be effective in reducing IBS symptoms in adults. Another study found that a low FODMAP diet may result in firmer and less frequent stools in IBS sufferers. 

Is a low FODMAP diet right for me?

In one study, researchers found that possible limitations may be resolved when a person follows a low FODMAP diet under the guidance of a healthcare professional. These limitations include cost, possible nutritional deficiencies and challenges with understanding and continuing the diet.

If you suspect you have IBS, the first step is to speak with your healthcare professional for a diagnosis.

Whether you’ve already been diagnosed with IBS or not, discuss with your healthcare professional whether the low FODMAP diet is right for you. 

Start the low FODMAP diet the right way

Need help with the low FODMAP diet? Our FREE dietitian-developed program will take you step-by-step through everything you need to know. The program includes a low FODMAP food guide and tips to make the diet work for you.

Sign up for the program now. Visit your healthcare professional for personal dietary advice.

Related:

• Eating out on a low FODMAP diet
• A guide to low FODMAP meal prep
• How to eat chocolate on a low FODMAP diet

Reviewed by the healthylife health experts August 2023.