Can reintroducing FODMAPs help reduce constipation?

Can reintroducing high FODMAP foods help ease constipation?

This idea might sound a bit counter intuitive, right? After all, reducing FODMAPs is meant to help resolve Irritable Bowel Syndrome symptoms.  We often find that for people who suffer from constipation, the low FODMAP diet helps reduce bloating, cramps, abdominal pain and gas, but it may not completely resolve the constipation. In fact, constipation issues can sometime worsen on the low FODMAP diet, as the diet can be lower in fibre if you aren’t eating the right balance of foods1.

So how can reintroducing FODMAPs help ease constipation…

FODMAPs are poorly absorbed in our small bowel, where they then have an osmotic effect which draws water into our intestines2. Next, they are fermented by our gut bacteria in our large intestine and create gas2. The combination of these two processes triggers IBS symptoms.

It’s the osmotic effect that can help reduce constipation. First the increased amount of water in our intestines can increase the water content of our stools3. The soluble fibre from the food we eat then acts like a sponge, which draws in the water, helping create stools that are larger and softer, therefore easier to pass4 5. Secondly, the osmotic effect helps food move through our digestive system faster and more easily, allowing FODMAPs to act like natural laxatives2.

According to accredited practicing dietitian, Joanna Baker, for constipation sufferers, it’s this combination of increased speed and better formation of stools that can help ease constipation and make bowel movements more regular. The trick is figuring out which FODMAP groups you can tolerate without causing other symptoms.

What FODMAP Groups Might Help Relieve Constipation

Lactose, excess fructose and polyols (sorbitol and mannitol) all create an osmotic effect in our intestines and can act like natural laxatives6 7. It is worth testing these groups to see if you can tolerate small amounts without triggering other symptoms.

How Do You Know When To Start Testing?

According to Joanna Baker, if your other gastrointestinal symptoms are now stable and constipation is your baseline symptom (the symptom that hasn’t improved during the elimination phase), then you can look at moving into the reintroduction phase. You can monitor the success of your FODMAP challenge tests by tracking gas production, cramping, bloating, and abdominal pain, as well as the number of bowel movements or lack of bowel movements you produce. A FODMAP challenge is successful if it helps your constipation and doesn’t trigger other symptoms.

When challenging your high FODMAP foods you may find that you need to leave a day in between each portion of the challenge food, to monitor symptoms. This is because when you are constipated, food can take longer to reach your large intestine and trigger symptoms.

Final Thoughts

Constipation is a frustrating symptom to manage. It’s worth experimenting and attempting to reintroduce some high FODMAP foods back into your diet to see if their natural laxative effects can help. Otherwise check out our 12 tips for managing constipation for some other helpful strategies to relieve symptoms.


1. Varney, J. Getting enough fibre on a low FODMAP diet. Monash University Low FODMAP Blog. 2014-12-02. Retrieved from: Retrieved on: 2017-07-09. (Archived by WebCite® at

2. Gibson, P. & Shepherd, S. Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach. Journal of Gastroentrology & Hepatology. 2010, Issue 25, 252-258. doi:10.1111/j.1440-1746.2009.06149.x 

3. Barrett, J., Gerry, R., Muir, J., Irving, P., Rose, R., Rosella, O., Haines, M., Shepherd, S., & Gibson, P. Dietary poorly absorbed, short-chain carbohydrates increase delivery of water and fermentable substrates to the proximal colon. Alimentary Pharmacology & Therapeutics. 2017: Volume 31, Issue 8, 874-882. doi:10.1111/j.1365-2036.2010.04237.x

4. Dietitians of Canada. Food Sources of Soluble Fibre. Dietitians of Canada. 2013. Retrieved from: Retrieved on: 2017-07-09. (Archived by WebCite® at

5. NZ Nutrition Foundation. FibreNZ Nutrition Foundation. 2015-03-23. Retrieved from: Retrieved on: 2017-07-09. (Archived by WebCite® at

6. Ladas, S., Haritos, D., Raptis, S. Honey may have a laxative effect on normal subjects because of incomplete fructose absorption. American Journal of Clinical Nutrition. 1995: Volume 62: Issue 6, 1212-1215. Retrieved from

7. Siegel, J. & Di Palma, J. Medical Treatment of Constipation. Clinics in Colon and Rectal Surgery. 2005: Volume 18: Issue 2, 76-80. doi:10.1055/s-2005-870887

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