What are FODMAPs & How Do They Affect Us?

What are FODMAPs?

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What are FODMAPs?

FODMAP sounds like acronym fit for a sci-fi movie! It is however a term created by researchers at Monash University, to represent a group of fermentable short chain carbohydrates known to cause unpleasant gastrointestinal symptoms (Monash University, 2015a; BPACnz, 2014).

The FODMAP acronym stands for:

Fermentable: The process through which gut bacteria degrade undigested carbohydrate to produce gases (hydrogen, methane and carbon dioxide)  (Monash University App, 2015).

Oligo-saccharides: Humans aren’t actually designed to be able to break down oligosaccharides, which means we all malabsorb them (Monash University App, 2015; Mansueto et al., 2015). There are two main types of oligo-saccharides. The first type is fructo-oligosaccharides (FOS) found in foods like wheat, rye, onions and garlic (Monash University App, 2015; Mansueto et al., 2015). The second type is galacto-oligosaccharides (GOS) found in legumes and pulses (Monash University App, 2015; Mansueto et al., 2015).

Disaccharides: The only disaccharide that causes IBS trouble is lactose. Lactose contains two sugars that need to be separated by an enzyme called lactase (Monash University App, 2015; Mansueto et al., 2015). If you don’t have enough lactase enzymes, your body won’t be able to separate the sugar units and you will malabsorb lactose (Monash University App, 2015; Mansueto et al., 2015). Lactose is found in milk, soft cheese, yoghurt, and ice cream (Monash University App, 2015).

Mono-saccharides: Fructose is a mono-saccharide. Research shows that approximately 30 to 40% of healthy individuals and people with Irritable Bowel Syndrome malabsorb excess fructose (Monash University App, 2015; Mansueto et al., 2015). Glucose is needed to help your body absorb fructose. Glucose acts as a ‘porter’ that co-transports the fructose across the intestinal cells and into your body (Mansueto et al., 2015).  When you consume more fructose than glucose your body isn’t able to effectively process the fructose and you may malabsorb it (Monash University App, 2015; Mansueto et al., 2015). Foods with equal glucose to fructose ratios can be easily absorbed.  Examples of foods containing excess fructose include honey, apples, and high fructose corn syrup (Monash University App, 2015).

And Polyols: Polyols are sugar alcohols that are found naturally in some fruit and vegetables as well as used as artificial sweeteners (Monash University App, 2015). They are incompletely absorbed across the small intestine, which is why they can cause gastrointestinal symptoms (Monash University App, 2015). Polyols include mannitol, sorbitol, maltitol, isomalt, and xylitol (Mansueto et al., 2015).

Research indicates that the low FODMAP diet could help up to 75% of Irritable Bowel Syndrome sufferers gain good symptoms control (Kings College, 2016; Taylor, 2015).

The low FODMAP diet is a medical diet and a specialised area of nutrition, which means it is important for you to seek help from a registered dietitian (Monash University App, 2015; Mansueto et al., 2015). The dietitian will make sure that your diet remains balanced and nutritionally adequate, as well as help you re-challenge and reintroduce FODMAP foods after a 2 to 8 week elimination phase.

Examples of FODMAP Foods

Please note this is not a complete list of high and low FODMAP foods. For an extensive and up-to-date list of high and low FODMAP foods please get the Monash Low FODMAP smartphone app.

Food CategoryHigh FODMAP FoodsLow FODMAP Food Alternatives
Vegetables Asparagus, artichokes, onions(all), leek bulb, garlic, legumes/pulses, sugar snap peas, onion and garlic salts, beetroot, Savoy cabbage, celery, sweet corn Alfalfa, bean sprouts, green beans, bok choy, capsicum (bell pepper), carrot, chives, fresh herbs, choy sum, cucumber, lettuce, tomato, zucchini
Fruits Apples, pears, mango, nashi pears, watermelon, nectarines, peaches, plums, banana (ripe) Banana (unripe), orange, mandarin, grapes, melon
Milk and dairy Cow’s milk, yoghurt, soft cheese, cream, custard, ice cream Lactose-free milk, lactose-free yoghurts, hard cheese
Protein sources Most legumes/pulses Meats, fish, chicken, firm tofu (in water), tempeh
Breads and cereal Rye, wheat-containing breads, wheat-based cereals with dried fruit, wheat pasta Gluten-free bread and sourdough spelt bread, rice bubbles, oats, gluten-free pasta, rice, quinoa
Biscuits (cookies) and snacks Rye crackers, wheat-based biscuits Gluten-free biscuits, rice cakes, corn thins
Nuts and seeds Cashews, pistachios Almonds (<10 nuts), pumpkin seeds

 (Table Sourced from: Monash University, 2015)

How Do FODMAPs Affect Us?

FODMAPs are a large group of dietary sugars (short chain carbohydrates) that can send us rushing to the toilet. The trouble starts when our small intestine fails to absorb these carbohydrates (Central Clinical School, 2015; BPACnz, 2014). The presence of FODMAPs causes water to be dragged into the small intestines which can lead to diarrhoea (Central Clinical School, 2015; BPACnz, 2014).

The malabsorbed sugars then travel on to our large intestine where they become ‘fast food’ for our gut bacteria (Central Clinical School, 2015; BPACnz, 2014). The bacteria use the FODMAPs to create energy (Central Clinical School, 2015). However, as the gut bacteria feast they rapidly ferment the short chain carbohydrates (Central Clinical School, 2015; BPACnz, 2014). This produces large quantities of hydrogen and methane (bad smelling) gases (Central Clinical School, 2015; BPACnz, 2014). These gases are why FODMAPs cause flatulence and can lead to constipation (Monash University, 2015a)

The combination of both gas production and water retention causes our intestines to expand, making us bloated (Central Clinical School, 2015). This bloating distends our intestinal walls causing the highly sensitive connected nerves to send abdominal pain signals to our brains (Central Clinical School, 2015).
The low FODMAP diet reduces diarrhoea, flatulence, bloating & distention, abdominal pain and constipation by reducing overall FODMAPs consumed to a level our bodies can tolerate (Central Clinical School, 2015; BPACnz, 2014).

The low FODMAP diet is a medical diet recommended for Irritable Bowel Syndrome patients (Central Clinical School, 2015; BPACnz, 2014).



  1. Monash University. What happens when FODMAPs are malabsorbed?. Monash University. 2015a. Retrieved from:http://www.med.monash.edu/cecs/gastro/fodmap/mal-absorption.html. Accessed on: 2015-03-06. (Archived by WebCite® at http://www.webcitation.org/6Wq4IpSL9)
  2. BPACnz. Irritable bowel syndrome in adults: Not just a gut feeling. Best Practice Journal. 2014: Issue 58. 14-25. Retrieved from http://www.bpac.org.nz/BPJ/2014/February/ibs.aspx
  3. Monash University App. Food Guide. The Monash University Low FODMAP Diet App. 2015: Version 1.3(180). Date retrieved: 2015-09-21. Retrieved from :http://www.med.monash.edu/cecs/gastro/fodmap/iphone-app.html. Accessed: 2016-01-15. (Archived by WebCite® at http://www.webcitation.org/6Wog73c8B)
  4. Mansueto, P., Seidita, A., D’Alcamo, A., Carroccio, A. Role of FODMAPs in Patients with Irritable Bowel Syndrome: A Review. Nutrition in Clinical Practice Journal. 2015-02-18. DOI: 10.1177/0884533615569886. Retrieved from http://ncp.sagepub.com/content/early/2015/02/17/0884533615569886
  5. Kings College London. FODMAPs. Kings College London. 2016. Retrieved from:http://www.kcl.ac.uk/lsm/research/divisions/dns/projects/fodmaps/index.aspx. Retrieved on: 2016-01-26. (Archived by WebCite® at http://www.webcitation.org/6epfl7bu7)
  6. Taylor, L. What to do if the low FODMAP diet doesn’t work for you? . Monash Low FODMAP Blog. 2015-08-27. Retrieved from:http://fodmapmonash.blogspot.co.nz/2015/08/-Other-IBS-treatments.html. Retrieved on: 2016-01-26. (Archived by WebCite® at http://www.webcitation.org/6epg0EKjc)
  7. Monash University. Frequently Asked Questions Section. Monash University. 2015b. Retrieved from http://www.med.monash.edu/cecs/gastro/fodmap/faq-index.html Retrieved on 2015-04-14.
  8. Central Clinical School, Monash University. The FODMAP Grand Tour Down Under: IBS relief [video] . Monash University. 2015-12-14. Retrieved from:https://www.youtube.com/watch?v=Z_1Hzl9o5ic&feature=share. Retrieved on: 2016-01-26. (Archived by WebCite® at http://www.webcitation.org/6ephIL1kH)