top of page

The 5 Most Common Causes of IBS Flare-Ups

By Sim Sekhon & Sascha McMeekin

Irritable Bowel Syndrome (IBS) is typically a life-long condition. Your IBS symptoms are likely to vary in intensity over time and can even switch from being diarrhoea-predominant to constipation-predominant. Periods of intense IBS symptoms, such as increase abdominal pain, bloating, diarrhoea and/or constipation, are known as ‘IBS flare-ups’.

The first thing to know about IBS flare-ups is that all IBS sufferers experience them at one time or another. They are simply part of living with IBS. This is important to recognise to avoid assigning any blame to yourself if your IBS symptoms suddenly intensify.

But there is no denying that IBS flare-ups can be frustrating! Even when it seems like you have taken all the precautions possible – you’re avoiding your trigger foods, drinking plenty of fluids, keeping to your toileting schedule – an IBS flare-up can suddenly come on. The cause of your flare-up determines what course of action will remedy your symptoms. So let’s take the first step to settling your symptoms and dive into the 5 most common reasons that I identify behind IBS flare-ups:

1. UFI: Unidentified FODMAP ingredient. In an ideal world we would have the time to analyse the back of the packet of all the foods that we buy, trawling for FODMAPs – but that is not a reality! Have you ever been flat out at work, skipped your lunch break and later found yourself at the shop buying the first snack you see? If so, you are not alone. Most often, when I analyse my client’s food diaries there is a UFI behind the flare-up. Whoops!

2. FODMAP stacking: It could be that although you are keeping to low FODMAP portions of foods, the overall FODMAP load in the meal was too much. This is very common, and very easy to do. This is called FODMAP stacking and will be explained in more detail in a future blog post – stay tuned!

3. Tolerance change: Your tolerance to a certain FODMAP could have changed with time. Research has indicated that tolerance to FODMAPs can change in as little at 3 months. Our bodies and environments are constantly changing so just because you used to tolerate a particular FODMAP does not mean that it will always be the case.

4. Meddling meds: There are many kinds of medications and supplements, which have gut- related effects. They could be drawing extra fluids into your intestines causing diarrhoea, they could be slowing down the motility of your intestines making you more constipated, or unbeknownst to you they could be keeping your IBS symptoms under control so when you stop taking them your symptoms could suddenly worsen! Always talk to your Doctor before making any changes to your medications.

5. Mind over matter: Stress and IBS are undeniably linked. Stress has been shown to have a direct impact on the functioning of our intestines. Stress is also known to be able to influence the way that we experience IBS symptoms. This means that on days when your stress levels are higher than usual you may have a lower threshold for your FODMAP triggers than when you are relaxed and calm. You'll find simple stress management techniques here.


No matter the reason behind the flare-up one thing is for sure, IBS flare-ups are never welcome! Luckily IBS is not known to do any harm to your health long-term, however, that does not mean that you need to continue to struggle with symptoms that are affecting your daily life.

Dietitians who specialise in IBS are trained to assess your medical history, medications, social situation, symptoms and of course your diet to identify the root cause for your IBS symptoms and your flare-ups along with way. You do not need to figure it out on your own. Your Dietitian will provide you with a plan tailored to your individual needs to get you back to feeling your best as soon as possible.

Sascha McMeekin is an Accredited Practising Dietitian and Monash-trained FODMAP Dietitian. She has helped hundreds of people just like you get in control of their IBS over the past 9 years. Find out more about her Master Your IBS Program here.


bottom of page