Skip to main content


With the rise of fad or trendy diets, you may have come across the term ‘FODMAP’ at least once.

But is a FODMAP diet a fad diet?

The term FODMAP is an acronym for “fermentable oligo-, di-, mono-saccharides, and polyols”. It can sound like a mouthful, but it is a term that encompasses foods with high concentrations of certain types of sugars and non-caloric sweeteners. You may recall that non-caloric sweeteners are found in diet sodas, chewing gum, and also naturally in foods such as grapes. Well, what is the issue with this class of foods? The ‘F’ in the acronym is where the problem arises: these sugars and non-caloric compounds commonly found in foods are fermentable. There may not be anything wrong with high FODMAP foods; in fact, high FODMAP foods tend to belong to the healthiest group: whole grains, fruits, and vegetables. However, for a subset of the general population, consuming FODMAP foods can produce bloating, irritability, and other gastrointestinal issues. We will shift and examine the anatomy of the small and large intestines to see why this occurs.

You Are an Ecosystem

The human body, and its various systems, crevices, and surfaces, provide a habitat for an overwhelming number of invisible inhabitants. You may be baffled to learn that 2-5 pounds of the number you see on the scale after weighing yourself comes from microscopic organisms: bacteria, fungi, archaea, and viruses 2. You are the landlord and they are your tenants. The overwhelming majority of these inhabitants are found in the gastrointestinal system, primarily in the large intestine or colon, as it is also referred to. You may wonder why we have such a diverse multitude of these organisms residing on and in our bodies. It turns out that humans, as a species, co-evolved with a number of these ‘microorganisms’. That is to say, over thousands of years, we provided shelter (on and in our bodies) and food to these little people while they provided services to us as well. These services came in the form of assistance with digestion, production of vitamins that we use, protection against deadly illnesses, among a whole host of other benefits3. The take-away here is that we live in harmony with these organisms.

Balance is the Key

As part of their normal biology, the bacteria that live within our large intestines take fiber and sugars, from the foods that we eat, and produce several chemical by-products. These include, as stated previously, vitamins, chemicals that help our immune system, as well as a number of different gases, such as carbon dioxide and methane. Excessive conversion of sugars into gases is what causes bloating and gas4. We may have certain ‘bad’ bacteria that infiltrate our large and small intestines and produce these gases. When our guts are out of balance and we have too many of these ‘bad’ bacteria living within them, it can lead to distress5. In particular, there are two common conditions that result from ‘dysbiosis’, or a gut that is out of balance.


It is estimated that 11% of the global population experiences a condition called Irritable Bowel Syndrome (IBS)6. It is a class of conditions characterized by the presence of any one or combination of the following symptoms: cramping, abdominal pain, bloating, gas, constipation, or diarrhea7. Dysbiosis, or an unbalanced profile of intestinal bacteria, has been recognized as a potential cause of IBS8. Similarly, another condition called small intestinal bacterial overgrowth (SIBO) is caused by the inappropriate growth of bacteria in the small intestine9. Relative to the large intestine, the small intestine should not have many bacteria living within it. When this situation arises, the extra bacteria produce gases leading to pain, discomfort, and bloating10.

How FODMAP Diets Ease SIBO and IBS 

The hallmark of low FODMAP diets is that they substantially reduce or completely eliminate several foods that are high in certain fermentable sugars and polyols. Employing these strategies minimizes the production of noxious gases, leading to a decrease in those symptoms described above 11. Often, a low FODMAP diet is implemented by eliminating one food item at a time and evaluating whether symptoms improve after its elimination12. This strategy is conducted with attentive monitoring by a health-care professional or Registered Dietitian. Several lines of research and clinical trials have confirmed that a low FODMAP diet is beneficial and effective for managing IBS and SIBO13 . Nevertheless, a low FODMAP diet should always be instituted with the supervision of a professional14. You can consult a list of high FODMAP foods by clicking here.


  1. Magge S, Lembo A. Low-FODMAP Diet for Treatment of Irritable Bowel Syndrome. Gastroenterol Hepatol. 2012;8(11):739-745.
  2. Ladizinski B, McLean R, Lee KC, Elpern DJ, Eron L. The human skin microbiome. Int J Dermatol. 2014;53(9):1177-1179. doi:10.1111/ijd.12609
  3. Barko PC, McMichael MA, Swanson KS, Williams DA. The Gastrointestinal Microbiome: A Review. J Vet Intern Med. 2018;32(1):9-25. doi:10.1111/jvim.14875
  4. Rajilić-Stojanović M, Jonkers DM, Salonen A, et al. Intestinal microbiota and diet in IBS: causes, consequences, or epiphenomena? Am J Gastroenterol. 2015;110(2):278-287. doi:10.1038/ajg.2014.427
  5. Hawrelak JA, Myers SP. The causes of intestinal dysbiosis: a review. Altern Med Rev J Clin Ther. 2004;9(2):180-197.
  6. Canavan C, West J, Card T. The epidemiology of irritable bowel syndrome. Clin Epidemiol. 2014;6:71-80. doi:10.2147/CLEP.S40245
  7. Ford AC, Lacy BE, Talley NJ. Irritable Bowel Syndrome. N Engl J Med. 2017;376(26):2566-2578. doi:10.1056/NEJMra1607547
  8. Dale HF, Lied GA. Gut microbiota and therapeutic approaches for dysbiosis in irritable bowel syndrome: Recent developments and future perspectives. Turk J Med Sci. March 2020. doi:10.3906/sag-2002-57
  9. Saffouri GB, Shields-Cutler RR, Chen J, et al. Small intestinal microbial dysbiosis underlies symptoms associated with functional gastrointestinal disorders. Nat Commun. 2019;10(1):2012. doi:10.1038/s41467-019-09964-7
  10. Ghoshal UC, Shukla R, Ghoshal U. Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome: A Bridge between Functional Organic Dichotomy. Gut Liver. 2017;11(2):196-208. doi:10.5009/gnl16126
  11. Reddel S, Putignani L, Del Chierico F. The Impact of Low-FODMAPs, Gluten-Free, and Ketogenic Diets on Gut Microbiota Modulation in Pathological Conditions. Nutrients. 2019;11(2). doi:10.3390/nu11020373
  12. Catassi G, Lionetti E, Gatti S, Catassi C. The Low FODMAP Diet: Many Question Marks for a Catchy Acronym. Nutrients. 2017;9(3). doi:10.3390/nu9030292
  13. Marsh A, Eslick EM, Eslick GD. Does a diet low in FODMAPs reduce symptoms associated with functional gastrointestinal disorders? A comprehensive systematic review and meta-analysis. Eur J Nutr. 2016;55(3):897-906. doi:10.1007/s00394-015-0922-1
  14. Bascuñán KA, Elli L, Pellegrini N, et al. Impact of FODMAP Content Restrictions on the Quality of Diet for Patients with Celiac Disease on a Gluten-Free Diet. Nutrients. 2019;11(9). doi:10.3390/nu11092220

Photo by Markus Spiske from Pexels.