The low FODMAP diet is a dietary treatment for irritable bowel syndrome (IBS) which restricts the intake of foods high in certain types of carbohydrates. If you suffer from IBS, this article will tell you …
The low FODMAP diet is a dietary treatment for irritable bowel syndrome (IBS) which restricts the intake of foods high in certain types of carbohydrates. If you suffer from IBS, this article will tell you everything you need to know about the diet and how it benefits symptoms of IBS.
What is IBS?
IBS is one of the most common disorders diagnosed by gastroenterologists worldwide. Diagnosis is usually reached after medical specialists have investigated and ruled out other possible causes of gastrointestinal discomfort such as coeliac disease, H. Pylori infection, ulcerative colitis, Chron’s disease and diverticulitis. IBS is an umbrella term for ongoing gastrointestinal symptoms such as constipation and/or diarrhea, bloating often accompanied by abdominal pain and distention, often with excessive wind (flatulence), without an underlying pathology.
The Low FODMAP Diet for IBS
The low FODMAP diet was put together by a group of researchers at Monash University in Victoria to help people with IBS control their symptoms. Researchers identified which foods are low and high in FODMAPs to help people with IBS identify which foods they should eat or avoid.
What are FODMAPs?
FODMAPs are a group of sugars that are not completely digested or absorbed in our intestines. When FODMAPs reach the small intestine, they move slowly, attracting water. When they pass into the large intestine, FODMAPs are fermented by gut bacteria, producing gas as a result. The extra gas and water cause the intestinal wall to stretch and expand which is what causes the abdominal bloating, often described as looking like a pregnant belly. Pain and discomfort is often associated with bloating, as well as excessive flatulence.
How Does the Low FODMAP Diet Work?
The low FODMAP diet restricts the intake of foods high in certain types of carbohydrates. The acronym “FODMAP” stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. These are not to be confused with fructose and lactose, two types of sugar found in fruit (fructose) and dairy (lactose). An intolerance to either fructose or lactose also causes symptoms of abdominal bloating and wind, but are usually diagnosed independently of IBS, although it is possible for IBS to be present in conjunction with a fructose or lactose intolerance.
When following a low FODMAP diet, it is advised to remove certain foods from the diet temporarily to reduce gastrointestinal symptoms, then slowly reintroducing foods over a period of time and monitoring symptoms. However, it is also important to address any underlying conditions that may be contributing to the development of FODMAP sensitivity.
Small intestinal bacterial overgrowth (SIBO) is a condition often present in people with medically diagnosed IBS  and can lead to an inability to tolerate certain types of carbohydrates such as those in the FODMAP category. While FODMAPS do not cause IBS, they can be a trigger for symptoms
Following a low FODMAP diet 
High FODMAP foods include:
Low FODMAP food alternatives
Artichoke, asparagus, cauliflower, garlic, green peas, leek, mushrooms, onion, sugar snap peas.
Eggplant, green beans, bok choy, capsicum, carrot, cucumber, lettuce, potato, tomato, zucchini.
Apples, apple juice, cherries, dried fruit, mango, nectarines, peaches, pears, plums, watermelon.
Cantaloupe, grapes, kiwi fruit (green), mandarin, orange, pineapple, strawberries.
Dairy and alternatives
Cow’s milk, custard, ice-cream, soy milk (made from whole soybeans), sweetened condensed milk, yoghurt.
Almond milk, brie / camembert cheese, feta, hard cheeses, lactose-free milk, soy milk (made from soy protein)
Most legumes / pulses, some marinated meats, processed meats.
Eggs, firm tofu, plain cooked meats and seafood, tempeh.
Bread and cereal products
Wheat/ rye/ barley based breads, breakfast cereals, biscuits and snack products.
Corn flakes, oats, quinoa flakes, quinoa / rice / corn pasta, rice cakes (plain), sourdough spelt bread, wheat / rye / barley free breads.
Sugars / sweeteners and confectionary
High fructose corn syrup, honey, sugar free confectionary.
Dark chocolate, maple syrup, rice malt syrup, table sugar.
Nuts and seeds
Macadamias, peanuts, pumpkin seeds, walnuts.
Low FODMAP diet recipes
The Monash University Low FODMAP Diet™ App is a great tool for anyone starting out on a low FODMAP diet as it includes an extensive list of allowable and avoidable foods as well as plenty of low FODMAP diet recipes. When working with an experienced nutrition professional, your clinician may also be able to provide you with a low FODMAP meal plan to get you started.
How to get enough fibre on a low FODMAP diet
As many sources of fibre are excluded on a low FODMAP diet such as legumes, certain grains, fruits and vegetables, meeting your daily fibre intake may prove challenging. People with IBS are recommended to consume 25-30g of fibre per day, which is consistent with the recommendation for the general population.
To ensure you are getting enough fibre, make sure you stick to the healthy eating guide by including a wide variety of low FODMAP fruits, vegetables and grains daily. You may also wish to use a fibre supplement, just make sure it is approved by your healthcare provider as being FODMAP friendly.
Low FODMAP diet limitations
The low FODMAP diet is a useful tool for those who suffer from IBS, but it does have its limitations and you should always consult your doctor before embarking on any new dietary regime. The diet restricts intake of certain types of carbohydrates which may be problematic if someone is following a restrictive diet for example, vegan or vegetarian diets where much of the protein intake comes from high FODMAP foods such as legumes.
It’s also important to note that a restrictive low FODMAP diet is associated with an increase in gut dysbiosis and should never be followed for more than 6 weeks . This is because FODMAPs are rich in prebiotic fibre that feed beneficial bacteria in the gut, and long-term adherence to the low FODMAP diet starves good bacteria which can end up worsening symptoms when these foods are reintroduced.
Always Use Under Correct Guidance
Before adopting this type of eating plan, it’s important to discuss it with a registered nutritionist or dietitian who can guide you on the proper implementation and reintroduction of FODMAP foods. Additionally, working with a practitioner that specializes in managing digestive conditions using naturopathic and nutritional medicine can help you navigate and treat the underlying cause, so that when you do reintroduce FODMAPS back in your diet you can avoid a symptom relapse.
- Ghoshal UC et al. Gut Liver. 2017;11(2):196-208.
- Vandeputte D et al. Microorganisms. 2020 Oct 23;8(11):1638.