Do I need to go on a low FODMAP diet?

A friend recently got in contact to ask some questions about the low FODMAP diet and it highlighted to me yet again how a low FODMAP diet is becoming something that most people have heard about, but few probably understand what it is and what it is used for.  So here’s what I shared with her.

A low FODMAP diet is one that reduces a person's intake of fermentable carbohydrates in their diet (these being Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols).  These are the types of carbohydrates that end up in our large bowel where they get fermented by the bacteria in our gut.  For most of us this is a positive thing and the bacteria are helping us out by digesting them for us, but for some this process causes all sorts of unwanted symptoms such as excessive wind, bloating, abdominal pain, diarrhoea and/or constipation.  These are all symptoms that people with IBS can suffer with and sometimes reducing our fermentable carbohydrates can help manage IBS.

But, firstly a person needs a clear diagnosis of IBS.    There are certain things that need ruling out before any dietary changes are made, including coeliac disease and Crohn’s disease.   In fact the test for coeliac disease relies on you having gluten in your diet to see if you are allergic to it, so you need this test before you start excluding it.  If no other causes can be found for your symptoms and you have been suffering for at least 6 months then a diagnosis of IBS may be made.

Only then should you take a look at diet.  Firstly, it is important to make sure that you eat a healthy and balanced diet in general and that your intake of fat, alcohol and caffeine are not excessive.  Drinking adequate fluid preferably water is also necessary.  It is also vital to look at lifestyle factors such as stress and eating habits e.g. regularity of meals, do you sit upright when eating and take time over your meals?

If none of this helps alleviate your issues then it is appropriate to trail a low FODMAP diet.  Trial is an important word here because a low FODMAP diet is not a long-term diet plan.  A low FODMAP diet should always be carried out under the supervision of a dietitian to ensure that you follow the diet correctly and that your intake is still balanced.  The diet should be followed for a period of 4-8 weeks, until symptoms have resolved (should FODMAPS be the issue!) and it is then vital to carry out a period of reintroduction in order to ascertain which foods/groups of FODMAPs are the trigger.  Once the reintroductions have been done in a systematic way, then your dietitian can help ensure that your diet is well balanced moving forward and that you do not end up cutting out huge numbers of foods from your diet.

It is important to remember that if your GP tells you to Google it (or anyone else for that matter) that you ask for a referral to a dietitian or find one privately.  Unless the diet is followed correctly you will not be able to tell accurately if any of the foods are causing your symptoms and are wasting your time.  You could also be doing more harm than good if you unnecessarily follow the diet restrictions for too long or misdiagnose yourself.     

IBS, Low FODMAPRuth Harveyfodmap, ibs, diet