Can the low FODMAP diet make you constipated?

Let us paint you a picture. You’ve been on the low FODMAP diet for a couple of weeks and all has been going well. Your windy gut has settled, your diarrhoea is 100% more manageable and the abdominal cramps are gone… You’ve been living the happy gut dream but everything is starting to feel a little sluggish. That brings us to the question – can the low FODMAP diet make you constipated?

This article is going to discuss what to do if constipation appears after you started the low FODMAP diet. If you suffer from chronic constipation check out this article instead.

Table of contents:

• Fibre & FODMAPS
• What can you do to reduce constipation?
• When to think about reintroducing FODMAPs

FODMAPs & Fibre

Fibre is critical for good bowel movements as it both softens and adds bulk to our stools which can make them easier to pass. It turns out though that we aren’t very good at eating fibre. Most of us don’t come close to eating the recommended amount of fibre per day and this issue can be compounded when you are on the low FODMAP diet (1, 2).

This is because lots of high FODMAP foods are also high in fibre (2). As you move on to the low FODMAP diet you end up swapping out some of these high fibre foods and this can lower your overall intake of fibre if you aren’t careful.

What can you do to reduce the constipation?

Up your fibre intake. One of the best ways to keep your gut happy and moving is by focusing on your fibre intake with these simple strategies:

1. Get your 7+ a day – that’s 2 handfuls of low FODMAP fruit + 5 handfuls of low FODMAP vegetables.
2. Sprinkle low FODMAP nuts and seeds on your salads, soups and porridge.
3. Add a low FODMAP serving of canned chickpeas, lentils, black beans or butter beans to your meals. Check out the Monash University FODMAP Diet App for more information.
4. Consider adding in a low FODMAP fibre supplement like ground linseeds/flaxseeds – this is a low FODMAP option in small serves.

Stay hydrated. There isn’t a magical number of glasses of water you have to drink. Instead, the goal is to get your urine to a light yellow or clear colour by the end of the day. Your urine should be the darkest when you first get up and then get progressively lighter as the day goes on. Focus on choosing low FODMAP drink options and avoid having lots of high caffeine or high sugar beverages.

Keep moving. Moving helps activate your digestive system and helps food move through your intestines. A gentle walk after a meal can do wonders for your digestion.

This means exercise also helps your bowel keep moving so find an exercise you love and commit to it.

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When to Reintroduce FODMAPs

If your other gut symptoms have settled and it’s just the constipation causing problems, then that can be a sign that you are ready to reintroduce high FODMAP foods. Some of the FODMAP groups can act like natural laxatives and allow your body to find a happy balance (3, 4, 5). Head on over to this article to find out more about the reintroduction process.

Final Thoughts

There are lots of easy tips you can use if you notice your gut becoming sluggish after starting the low FODMAP diet. Just remember the low FODMAP diet isn’t for life and we highly recommend you move onto the reintroduction phase after 2-4 weeks.

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