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gut health

What Is The Low FODMAP Diet?

You may have heard the term ‘low FODMAP’ more and more recently, but what is the low FODMAP diet? A low FODMAP diet is relatively new in the nutrition world and is something gaining more traction and use as the years go on. It is a diet that is occasionally given to patients by dietitians and nutritionists when they have continuous gastrointestinal symptoms.

This blog is for you if you have been suggested to try this diet or want to find out more. This blog aims to cover WHAT this diet is, WHO it is for, and HOW it works. Read on to find out more about FODMAPs and a brief summary of the low FODMAP diet.

What is the Low FODMAP diet?

The low FODMAP diet is one which is low in fermentable carbohydrates1. FODMAPs are Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols. These are certain dietary carbohydrates that are poorly absorbed and make it to the large intestine undigested which triggers IBS-like symptoms in some people. A low FODMAP diet is occasionally used to reduce symptoms, such as wind, bloating and pain2 and identify dietary triggers of symptoms. Evidence has shown that some people have up to a 85% improvement in symptoms when a low FODMAP diet is utilised3, it is utilised in some treatment plans for IBS and SIBO.

How does the low FODMAP diet work?

These types of carbohydrates are thought to cause gastrointestinal symptoms by two different methods; either by drawing more water into the gut or they are rapidly fermented in the gut which produces gas5. Together this gas production and water delivery can cause distension of the gut causing pain, bloating, flatulence and change in the gut movements. Not everyone reacts badly to these types of carbohydrates- they are part of a usual diet for many people with no poor effect. However, those with IBS or some other gastrointestinal conditions are thought to have visceral hypersensitivity. This is a fancy way to say that the gut is more prone to inflammation and pain so will react in a different way to dietary triggers.

Therefore, in those with a sensitive gut due to a medical condition, a low FODMAP diet may be helpful for a period of time to reduce the inflammation as well as figure out any particular foods which cause symptoms.

The low FODMAP diet is used in 3 phases4

  1. A period of restriction of dietary FODMAPS which allows time for the gut to settle down and
    symptoms to resolve.
  2. FODMAP reintroduction. This section allows for dietary trials with small amounts of
    FODMAPS to see what the gut can tolerate and identify triggers
  3. FODMAP personalisation. This phase is where your diet is tailored to what the gut can handle
    and in specific quantities with the aim of it being a sustainable diet.
Top Tips for a Low FODMAP Diet
  • A low FODMAP diet should be done with supervision and guidance of a clinical professional, preferably a specialist registered dietitian. This is to ensure there are no nutritional deficiencies and your body still receives the care and nutrition it requires.
  • This diet is not for everyone. A diagnosis of IBS or SIBO does not automatically mean you must go Low FODMAP, there are plenty of other, less-restrictive avenues to explore first.
  • The low FODMAP diet is not forever. It is a difficult diet to follow, it is restrictive and is only meant to be followed for a small period of time.
If you would like to see if this diet is for you, or you would like further, personalised dietary guidance please GET IN TOUCH FOR A FREE 15 MINUTE CONSULTATION CALL. Speaking to someone with expertise in all areas of gut health and diet might be the answer to your condition, you could have drastic positive changes on the horizon. Get in touch today, for FREE, to see if I can help you.


You can book in with the IBS dietitian Bath to see what support you can get, be it at home or in clinic.

The information provided above is not meant for the purposes of medical diagnosis, treatment or prescribing any form of medicine for any condition. This information is not intended to replace the advice of a healthcare professional. Please ensure to consult a qualified health care professional with any questions you may have.

1. Staudacher HM, Whelan K. The low FODMAP diet: recent advances in understanding its mechanisms and efficacy in IBS. Gut. 2017 Aug 1;66(8):1517-27.
2. Ong DK, Mitchell SB, Barrett JS, Shepherd SJ, Irving PM, Biesiekierski JR, Smith S, Gibson PR, Muir JG. Manipulation of dietary short chain carbohydrates alters the pattern of gas production and genesis of symptoms in irritable bowel syndrome. Journal of gastroenterology and hepatology. 2010 Aug;25(8):1366-73.
3. Staudacher HM, Lomer MC, Anderson JL, Barrett JS, Muir JG, Irving PM, Whelan K. Fermentable carbohydrate restriction reduces luminal bifidobacteria and gastrointestinal symptoms in patients with irritable bowel syndrome. The Journal of nutrition. 2012 Aug 1;142(8):1510-8.
4. Whelan, K. et al. “The low FODMAP diet in the management of irritable bowel syndrome: an evidence-based review of FODMAP restriction, reintroduction and personalisation in clinical practice.” Journal of Human Nutrition and Dietetics 31 (2018): 239–255.