Do you really need a low-FODMAP diet to help with IBS symptoms? Why the experts are divided on the benefits

Healthy FODMAP foods in the shape of a heart

Credit: Getty

Strong Women


Do you really need a low-FODMAP diet to help with IBS symptoms? Why the experts are divided on the benefits

By Anna Bartter

Updated 2 years ago

5 min read

If you struggle with gut conditions such as IBS or simply want to beat the bloat, a low-FODMAP diet might sound like the solution. But do they really work, or should we be taking them with a pinch of salt? 

If you’re one of the approximately 20% of people in the UK who struggle with IBS, you’ll probably have come across the idea of a low-FODMAP diet at some point. And the data seems impressive, with studies showing that a low-FODMAP diet is “superior to all other interventions” in treating IBS symptoms from bloating to abdominal pain.

But is it really the magic bullet it appears to be? While it’s tempting to follow the diet religiously, critics suggest that, in the long term, it might actually be detrimental to gut health. So, who should we believe? We turned to the experts for their take. 

What is low-FODMAP food?

FODMAP is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. 

“FODMAP stands for a lot of big words but they are basically types of carbohydrates found in foods that we may struggle to digest fully,” explains registered nutritionist Eva Humphries. “There are many foods that we can’t fully break down, but where FODMAP foods differ is that they ferment very easily. This fermentation is associated with bloating and digestive discomfort in susceptible individuals.

Low-FODMAP foods are generally lower in fermentable carbohydrates and the less fermentation there is, the less likely it is that bloating and discomfort will result.”

And the science seems to back this up. “The diet was developed by researchers at Monash University in Australia,” says nutritional therapist Nishtha Patel. “They found that certain types of carbohydrates (FODMAPS) were poorly absorbed in the small intestine and fermented by gut bacteria in the large intestine, causing symptoms such as bloating, gas and abdominal pain in people with IBS. By eliminating or reducing high-FODMAP foods from the diet, IBS symptoms could be significantly reduced in many people.”

Indeed, research shows that up to 75% of people with IBS experience significant improvements in their symptoms by following a low-FODMAP diet. However, if you are struggling with IBS symptoms – which can range from bloating and discomfort to constipation and diarrhoea – it’s vital to consult your GP to rule out any other underlying causes before following any kind of diet plan. 

What does a low-FODMAP diet look like? 

“A low-FODMAP diet avoids high-FODMAP foods over a specific period of time, usually for two to six weeks,” advises Humphries.

During this time, you’ll be advised to steer clear of foods such as certain vegetables, fruits, milk, beans, pulses and some grains, and up your intake of low-FODMAP foods like poultry, fish, eggs, certain fruits and vegetables and lactose-free dairy products.

It can be tricky to get your head around what’s what. For example, watermelons are high FODMAP but cantaloupe melon isn’t, so it’s important to do your homework for the diet to have the desired effects, which is where some of the criticism comes into play. 

In addition, it’s important to note that even the researchers don’t advocate this as a long-term diet solution - rather, it’s a good, short-term way to find out what your trigger foods might be. After a maximum of six weeks, you can begin the reintroduction phase of the diet, where you slowly reintroduce eliminated foods to your diet. This should determine which foods are tricky for you to digest. 

What are the downsides of a low-FODMAP diet? 

You shouldn’t try it without taking advice first

It’s important to note that any kind of diet that involves eliminating of restricting certain food types should only be undertaken under the supervision of a qualified professional, so don’t be tempted to settle for a quick google search.

“There is potential that simply following a low-FODMAP diet may distract from addressing the root cause of gut health issues,” warns Humphries. “Our gut is home to a significant population of microbes which live off things we can’t fully digest, be it fibre, FODMAPs or other foods. Depending on the balance of these microbes, they can either make us exponentially healthier or contribute to niggling issues, including bloating and digestive discomfort – it’s important to know what is causing the issue.”

It can seem restrictive

“The diet sounds like a lot of restriction,” acknowledges Humphries, “but the idea behind the FODMAP diet is to swap high-FODMAP foods for low-FODMAP ones. It’s a swap rather than an avoidance-based diet.” So, don’t be tempted to cut back too much, otherwise you could risk eliminating important nutrients. 

Research is ongoing

“Long-term studies on the impact of the low-FODMAP diet are still lacking,” advises Humphries. “Based on the current understanding, this approach should only be followed for short periods of time,” she says. Two to six weeks, max. 

Salmon peppers and low FODMAP foods

Credit: Getty

Your microbes might suffer

The key to good gut health is diversity, and while a low-FODMAP approach removes fuel from ‘bad’ gut microbes, it may also leave you at risk of lack of diversity and not having enough ‘good’ microbes. “FODMAPs are only a teeny-tiny part of the picture,” Humphries reminds us. “As such, it could distract from taking a more holistic look at gut health.”

It might fuel restrictive eating patterns

Last but not least, there is potential for a low-FODMAP diet to feed into restrictive dieting rhetoric, and given that 98% of eating disorder sufferers also struggle with IBS symptoms this is a very real problem. “As a nutritionist, I sadly see a fair share of clients that are scared to eat high-FODMAP foods for fear of bloating,” agrees Humphries. “Unless properly planned, the diet may not adequately meet nutrient requirements.”

“Gut health issues can seem really daunting but remember you don’t have to suffer alone,” assures Humphries. “Working with a qualified nutritionist or dietitian offers a clear, personalised approach that takes the guesswork out of gut health. The science in this field is constantly evolving and there are a whole host of new approaches and tests that can be utilised.”


Images: Getty

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