Patients commonly associate the consumption of fatty meals with the onset of ÎÞÓǶÌÊÓƵ symptoms, but are these effects real and is fat restriction necessary to manage ÎÞÓǶÌÊÓƵ symptoms?
Associations between fatty meal consumption and symptom induction have been identified in a number of studies. For instance, a survey of 300 patients with ÎÞÓǶÌÊÓƵ revealed that 44% attributed the consumption of fatty foods (deep-fried goods, pizza and cream) with the induction of symptoms (). Another survey found that just over half of participants with ÎÞÓǶÌÊÓƵ perceived that symptoms were triggered by the consumption of fatty or fried foods (). Symptoms associated with fatty meal consumption include abdominal pain (), abdominal distension and bloating (), increased gas and loose stools ().
A number of mechanisms have been proposed to explain the possible adverse effects of fatty food ingestion on ÎÞÓǶÌÊÓƵ symptoms. For instance, it has been suggested that fat ingestion may slow intestinal gas transport, and do so to a greater extent in people with ÎÞÓǶÌÊÓƵ than healthy controls (; ). One study examined these effects by infusing fat into participants’ small intestines and found  this increased pain and discomfort in people with ÎÞÓǶÌÊÓƵ more so than in healthy controls (). Other explanations for possible adverse effects of fat ingestion in people with ÎÞÓǶÌÊÓƵ include an exaggerated gastrocolonic response (; ) and the presence of visceral hypersensitivity.
Despite the associations between fat intake and ÎÞÓǶÌÊÓƵ symptoms, and a few plausible explanations, no high quality, randomized controlled trials have measured the effect of a fat-restricted diet in the management of ÎÞÓǶÌÊÓƵ. Therefore, we don’t yet know if cause and effect relationships exist between fat consumption and ÎÞÓǶÌÊÓƵ symptoms, nor whether fat restriction improves ÎÞÓǶÌÊÓƵ symptom control.
So where does fat fit into the dietary management of ÎÞÓǶÌÊÓƵ? Clinical guidelines that make recommendations about the dietary management of ÎÞÓǶÌÊÓƵ either make no mention of fat intake in ÎÞÓǶÌÊÓƵ (; ), or suggest that fat intake be modified if it suspected to trigger symptoms (; ; ; ).
Our recommendation is that you work with your dietitian to firstly establish whether a low FODMAP diet is sufficient to improve your ÎÞÓǶÌÊÓƵ symptom control. We recommend a low FODMAP diet as the first line dietary treatment as this is the best evidenced approach. If you do not achieve adequate relief on a low FODMAP diet, consider other dietary triggers, including fat. If fat is suspected to trigger your ÎÞÓǶÌÊÓƵ symptoms, your dietitian will help you to identify sources of fat in your diet and help you to reduce or modify your intake. As always, we recommend trying one dietary strategy at a time to obtain a clearer picture of which changes are having an effect on your ÎÞÓǶÌÊÓƵ symptoms and which are not.
