Non-FODMAP Dietary Triggers of IBS Symptoms

Non-FODMAP Dietary Triggers of IBS Symptoms Blog

Chloe Swiney - Research Dietitian, 26 March 2024

Living with irritable bowel syndrome (IBS) often involves navigating a complex relationship with food. While the low FODMAP diet has gained popularity as a method to manage IBS symptoms, it's important to recognise that not all triggers are solely related to FODMAPs. In fact, certain foods considered low in FODMAPs can still cause discomfort or exacerbate symptoms for individuals with IBS. If through undertaking the low FODMAP diet you do not achieve good symptom control, working with a FODMAP-trained dietitian can help you identify other possible dietary triggers.

Let's delve into why some seemingly “safe” foods on the low FODMAP list may still pose challenges for those with IBS.


For many, coffee is a morning ritual, but for individuals with IBS, it can be a double-edged sword. While coffee itself is low in FODMAPs, anecdotally many people note that it can stimulate the gastrointestinal tract, leading to cramping, diarrhoea, or urgency in some individuals.

Unfortunately, the studies on coffee's effect on motility are limited, but those that have been conducted did find that both caffeinated and decaffeinated coffee increased colonic motor activity (activity in the muscles of the colon/bowel).[1] Caffeinated coffee had a slightly larger effect, however, overall this suggests that it is the complex combination of the elements in coffee (caffeine, polyphenols etc) that affect the muscles within the bowel.[1]


Alcohol, particularly in excess, is notorious for its digestive side effects. While certain alcoholic beverages like wine and spirits are low in FODMAPs, they can still wreak havoc on IBS symptoms. Alcohol is thought to have a direct effect on the function of the gastrointestinal tract, possibly through alterations in intestinal motility, permeability and intestinal absorption.[2] These effects may account for commonly reported symptoms such as diarrhoea, abdominal pain and indigestion.[3-5] Moderation is key when it comes to alcohol consumption. This is important for general health and for people with IBS. If alcohol is suspected as causing symptoms then alcohol reduction or elimination may be considered.

Fatty Foods:

Fatty foods can be problematic due to their impact on gut motility and digestion. High-fat meals may slow down the emptying of the gut, leading to feelings of fullness, bloating, and discomfort.[6] As people with IBS tend to have an overly sensitive gut wall, the increase in these digestive symptoms can be felt more prominently and painfully.[7]

If you suspect fatty foods trigger your IBS symptoms, you could try reducing very high fat meals and desserts, choosing leaner cuts of meat, and avoid very high fat cooking methods such as deep frying.

Carbonated Drinks:

Anecdotally, carbonated drinks, including soda and sparkling water, have been suggested to aggravate IBS symptoms in some people and one IBS guideline recommends reducing intake of fizzy drinks to improve IBS symptoms. While there is not much evidence to show that fizzy drinks trigger IBS symptoms, it is theorised that they may distend the stomach and intestines, leading to bloating and discomfort. If you suspect fizzy/carobinated drinks are a problem, you could opt for plain water or herbal teas instead.[9].

Spicy Foods:

Spicy foods can add flavour and excitement to meals, but they can also spell trouble for individuals with IBS.[3] While foods themselves are often low in FODMAPs, the “heat” from spicy foods, produced by a natural chemical called capsaicin, can exacerbate symptoms such as abdominal pain and diarrhoea.[9]

Experimenting with milder spices and avoiding excessive use of hoter varieties can help minimise discomfort.


The effects that all these foods have on the gut happen in most individuals. The difference when it comes to those with IBS is that they are felt more strongly due to a highly sensitive gut.

While the low FODMAP diet can be effective in managing IBS symptoms, it's essential to recognise that not all triggers are diet or FODMAP-related. For some people, their IBS is more sensitive to non-dietary factors such as stress and anxiety, or non-FODMAP triggers such as coffee, alcohol, fatty foods, carbonated drinks or spicy foods. If your symptoms are not adequately improved on Step 1 of the FODMAP diet, work with a health professional to identify other diet or non-diet related triggers.

A FODMAP-trained dietitian can help you to identify other diet related triggers such as what was covered in this blog.

Of course, it is recommended you make one dietary change at a time, monitor symptoms and bring the food or drink back into your diet if there is no improvement in your symptoms. Understanding your personal IBS triggers and making informed dietary choices can empower you to better manage your IBS and improve your quality of life.


  1. Iriondo-DeHond A, Uranga JA, Del Castillo MD, Abalo R. Effects of Coffee and Its Components on the Gastrointestinal Tract and the Brain-Gut Axis. Nutrients. 2020;13(1):88. Published 2020 Dec 29. doi:10.3390/nu13010088
  2. Bode, C. and J.C. Bode, Alcohol's role in gastrointestinal tract disorders. Alcohol Health Res World, 1997. 21(1): p. 76-83.
  3. Simren, M., et al., Food-related gastrointestinal symptoms in the irritable bowel syndrome. Digestion, 2001. 63(2): p. 108-15.
  4. Nazer, H. and R.A. Wright, The effect of alcohol on the human alimentary tract: a review. J Clin Gastroenterol, 1983. 5(4): p. 361-5.
  5. Reding, K.W., et al., Relationship between patterns of alcohol consumption and gastrointestinal symptoms among patients with irritable bowel syndrome. Am J Gastroenterol, 2013. 108(2): p. 270-6.
  6. Cozma-Petruţ A, Loghin F, Miere D, Dumitraşcu DL. Diet in irritable bowel syndrome: What to recommend, not what to forbid to patients!. World J Gastroenterol. 2017;23(21):3771-3783. doi:10.3748/wjg.v23.i21.3771.
  7. Major G, Pritchard S, Murray K, et al. Colon Hypersensitivity to Distension, Rather Than Excessive Gas Production, Produces Carbohydrate-Related Symptoms in Individuals With Irritable Bowel Syndrome. Gastroenterology 2017;152:124-133 e2.
  8. Sikorska-Zimny K, Beneduce L. The Metabolism of Glucosinolates by Gut Microbiota. Nutrients. 2021;13(8):2750. Published 2021 Aug 10. doi:10.3390/nu13082750
  9. Irritable bowel syndrome in adults: diagnosis and management. London: National Institute for Health and Care Excellence (NICE); April 2017.
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