We’re pleased to welcome Martin Cohen, Registered Nutritional Therapist and founder of The IBS and Gut Health Clinic, to the Ferrocalm blog.

Martin specialises in supporting people with IBS and complex gut symptoms, particularly those who have been through tests, been told “it’s just IBS,” and left without enough practical guidance. Since qualifying from the College of Naturopathic Medicine in 2015, he has worked with patients across a wide range of digestive issues, including IBS, SIBO, IBD, reflux, and gut symptoms influenced by stress, hormones or medication.

In this guest article, Martin explores the low-FODMAP diet, why it can be helpful for managing symptoms, and why it should usually be seen as a step in the journey rather than the final destination.

What is the Low FODMAP diet?

Foods can be a common trigger for increasing digestive symptoms, and the low-FODMAP diet can connect the dots between seemingly different foods. It can provide clarity around triggers and help make day-to-day symptoms more predictable. However, it's important to be clear on what's managing symptoms versus what's addressing the root cause.

The low-FODMAP diet is there to reduce symptoms. Not treat.

The process is common. Tests are clear, there's a diagnosis of IBS, and perhaps you've been handed a print-out of a low-FODMAP diet. This is what I hear from at least 80% of the people I support.

The remaining 20% have found the low-FODMAP diet online and downloaded the Monash FODMAP app, going about this (potentially confusing) diet without support.

In either case, following the diet for a few weeks can indicate how helpful it may (or may not) be. But sometimes the worst thing that can happen is that the low-FODMAP diet has been too helpful.

Let me explain.

The more symptoms that improve with the diet, the scarier it can be to come off it. This can leave you in a limbo situation. Experiencing few symptoms but living in fear of a range of foods.

In this article I’ll dig into the FODMAP diets role and why a high FODMAP diet is actually what we’re working towards.

What IBS Can Actually Feel Like

For many people, and maybe this is your experience too, IBS isn't a bit of bloating and having to avoid a couple of known and easily avoidable food triggers.
It can be a situation with chronic pain and discomfort, anxiety and stress, and always being worried about when the next bowel movement might be — be that in 4 days' time or at a moment's notice.
So, when the low-FODMAP diet helps, it can feel like a godsend. Less pain, less fear around food, and some predictability.
But think of the diet as a rest stop on a journey, not the destination. At some point, that means relaxing and expanding the diet again, alongside a more active form of treatment or support.

Who Is the Low-FODMAP Diet Meant For?

The diet was created to remove or reduce levels of specific fermentable carbohydrates. These are found in a wide range of plant foods.

At first, taking all of these natural, unprocessed foods out of the diet might not make much sense, especially when we hear is that fibre is really important for gut health. And it is. But when the gut is irritated or out of balance (more on this soon), these fibres and sugars — the fermentable carbohydrates — can cause symptoms to increase.The issues are not due to the foods, but due to the way the gut is handling and dealing with these foods during the digestive process.

From a research perspective, the diet tends to be more effective for IBS-D (diarrhoea-predominant) than IBS-C (constipation-predominant). Where it works, it can reduce a range of symptoms, including bloating, pain, wind and irregular bowel habits.
Once you're a few weeks in, there are generally three outcomes of the diet:
It eliminates symptoms completely. This is the outcome most people hope for — but it's also the one that can make reintroduction feel riskiest, because when something is working this well, it's natural to be reluctant to change anything.

It reduces symptoms but doesn't resolve them fully. This is the most common outcome, and it usually points to other root causes still being active alongside diet.

It doesn't help at all. This happens more often than people expect. It usually means FODMAPs weren't the main driver of food reactions in the first place, and continuing to restrict food long term is unlikely to help — and can create new problems of its own. For example, it's common for people to continue with the diet for months in the hope that it's going to start working.

In all three scenarios, FODMAPs often stay restricted long-term — which isn't ideal for gut health.

Why Reintroduction Feels Risky (and How It Actually Works).

When looking at the FODMAP dietary structure, there are three phases:

• Eliminate
• Reintroduce
• Maintenance 

As mentioned, if the first phase has been helpful, why reintroduce? Some people I've supported weren't even given the information from their doctor that there was a second or third phase.

Looking at the low-FODMAP diet in isolation, its aim is to find the least restrictive diet you can follow long term, the maintenance phase.
While reintroductions can be scary, it's an important step forward. Here's what that can look like in practice:
One FODMAP subgroup is tested at a time — for example, fructans, then lactose, then polyols. Each is introduced in small, increasing doses over a few days, while everything else in the diet stays low-FODMAP.

This step-by-step approach isolates exactly which types and amounts of FODMAPs are genuine triggers, rather than assuming an entire food group needs to stay off the table permanently. Done with support, working through all the groups typically takes around 6–8 weeks.

Reactions don't equal damage. I'll repeat that: reactions don't equal damage.

And while going slowly during the reintroduction phase is important, so as not to trigger a strong increase in symptoms, symptoms only tend to last as long as it takes for the food to pass through the gut.

Example from my clinic 

Here’s what it looked like for one client I was supporting a client with IBS. They had been following a low-FODMAP diet in its most restrictive form for several months, which improved their symptoms by 90% — a good starting point to manage symptoms. 
By starting the reintroduction process, we soon discovered that it was only onion that caused their symptoms to flare. So, we were able to expand the diet and reintroduce more FODMAPs.

The Bigger Picture

If nearly all of your focus has been on trying to eliminate foods and restrict FODMAPs, this might feel like you've backed yourself into a bit of a corner. I've seen plenty of clients where this has been the case — many of whom have also removed even more foods they're suspicious of and still have unpredictable reactions. Perhaps this sounds familiar too?

Either way, whether it's 5 foods you've eliminated or 50, the question to ask isn't "What foods am I reacting to?" but "Why is my gut behaving this way?" This is where we start thinking about root causes.

The issue with the diet, especially when it's followed in its most restrictive form over the long term, is that it removes one of the main fuel sources that supports the growth of beneficial bacteria in the gut. Essentially, this leads to a poorly fed, less diverse and less resilient microbiome.
The aims of this approach can be to:

• keep the diet as high-FODMAP as is tolerated
• address the root cause so all foods can be reintroduced without issue

Root Causes

To simplify the gut and how IBS develops, picture a building. With all the bricks in the right place, this creates a really strong, resilient structure — one that doesn't move around or wobble in the wind.

However, there are risk factors that nudge those bricks out of place. Over time, these can contribute to the gut symptoms described as IBS, and the food reactions that follow.

These risk factors include:

• Genetics
• Long-term dietary patterns that contain processed foods and low fibre
• Medications, such as antibiotics
• Food poisoning
• Gastrointestinal infections (e.g. norovirus)
• Abdominal surgery
• Life stresses

As the building loses stability, it starts to lean and wobble. This is reflected in the gut as changes to the microbiome and the gut lining — and it's what produces unpredictable symptoms.

While just one of these risk factors might trigger gut issues, there can be a cumulative effect.

So, in the broader sense, addressing the underlying issue can involve putting the right care, support and scaffolding around the building to bring it back to a place of stability and resilience.

In practice, that scaffolding tends to fall into a few areas and the considered introduction of supplements and lifestyle adjustments to support with: 

• Identifying and calming any ongoing gut irritation, or low-grade inflammation
• Supporting microbiome diversity and balance
• Addressing the nervous system side of the gut-brain connection

Particularly from a nervous system perspective, research has found that mindfulness meditation has proved as helpful as a low-FODMAP diet.

Conclusion

Yes, the low-FODMAP diet can be helpful to calm symptoms, but staying on it for too long — particularly in the most restrictive elimination phase — can lead to reduced microbiome diversity and increased fear and stress around reintroducing foods.

Moving towards a wider, higher-FODMAP diet can feel like a long way away, and like leaping too far, too quickly.
That's why reintroduction is normally done gradually and one step at a time, ideally with a practitioner guiding the process — checking in on symptoms, adjusting the pace, and helping you tell the difference between a genuine trigger and a normal, harmless reaction. You don't need to figure this out alone, and you don't need to choose between permanent restriction and going back to square one.

If you recognise yourself in this article — stuck in the elimination phase, afraid to reintroduce, or still reacting to foods despite months of restriction — that's usually a sign it's time to look at what's driving your symptoms, not just which foods to avoid next.

About Martin - @ibsguthealthclinic

Martin Cohen is a Registered Nutritional Therapist (Dip CNM, mBANT, mCNHC) and founder of The IBS and Gut Health Clinic. He started the clinic after seeing too many patients who'd been through every test their GP or gastroenterologist could offer, been told "it's just IBS," and sent away with little more than a leaflet. Martin believes digestive symptoms always have a cause — and addressing it is the key to resolving them.
He trained at the College of Naturopathic Medicine, graduating in 2015, and is a registered member of both BANT and CNHC. Since qualifying, he's worked with patients across a wide range of gut issues, including IBS, SIBO, IBD, reflux, and more complex cases tied to stress, hormones, or medications.