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What is a FODMAP?

If you have recently been diagnosed with IBS, your doctor or dietitian may have suggested you try the Low FODMAP Diet. They likely told you that following this specific diet may reduce your IBS symptoms. That sounds great, but now you’re wondering, what is a FODMAP?

Illustration of glucose, fructose and galactose molecule

Illustration by Alex Davey

Breaking Down FODMAPs

The word FODMAP sounds ridiculous because it’s an acronym. It stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. If your brain just exploded don’t worry, I’ve got you!

Before we move any further, the first thing you need to know is that a “saccharide” is a sugar molecule. These molecules can stand alone or be bonded together into “chains.” When your dietitian talks to you about “short-chain” and “long-chain” foods, they are talking about how many molecules are bonded together as they float around in your digestive system.

A monosaccharide floats around on its own as a single molecule. A disaccharide, however, is two molecules bonded together. An oligosaccharide means there could be anywhere from 3 to 10 molecules bonded together. Just so we’re clear, FODMAPs are generally “short-chain” compounds.

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The Exception

You’ve been doing great, so stay with me! Polyols (the “P” in FODMAP) are long chains of sugar alcohols. These are a different kind of compound than a “-saccharide,” and normally end in “-ol.” These can be massively long; bonding together hundreds of molecules at a time.

When looking for a polyol on a label, look for things ending in “-ol” (sorbitol, mannitol, maltitol, xylitol, lactitol, and erythritol are common). Isomalt is also a polyol. This one is worth memorizing as it’s harder to recognize on a label.

FODMAP Subgroups

I thought I had this all figured out until I met with my dietitian for the first time. As it turns out the FODMAP groups are shorthand for several subgroups. Fear not, I said I’ve got you!

In fact, I made an illustrated guide to help you interpret what people are talking about. I thought this might be handy after my doctor, dietitian, and re-challenge booklet used three different terms to talk about the same food. Because why the heck not?

This chart can come in pretty handy, so you might want to PIN IT!

Infographic titled: What is a FODMAP? with desctiption of each FODMAP group

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© Copyright 2017 Amy Agur – The Low FODMAP Diet

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Leave a Comment

  • mike

    this is the first article / book/ resource that i have read that explains the FODMAP acronym in a layman’s term. i read one book that said it was for the layman but i could not understand half the article !!!!!

    • Amy Agur

      Hi, Mike!

      I had exactly the same problem when I started the Low FODMAP Diet! I’m so glad you found this resource helpful.

  • Jennifer

    What a great resource! The cute pictures grabbed my attention on Pinterest but the way you describe everything with such care is what won me over. I’m actually beginning to understand everything, it feels great!

    • Amy Agur

      Hi Jennifer!

      Cute pins get me every time! Glad I could help you understand FODMAPs a little better!!


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