Are onions low FODMAP?

High FODMAP, usually limited

Onions are high FODMAP and are usually limited during the elimination phase.

High FODMAP

Fructan

Last reviewed October 24, 2026

Onions on a low FODMAP diet

Leave onions out during the elimination phase, which usually lasts two to six weeks.
Use one of the lower-FODMAP swaps below instead.
High FODMAP doesn't mean forever: during reintroduction, many people find they tolerate some high FODMAP foods in smaller amounts.

Which FODMAPs are in onions

Fructan: Fructans are chains of fructose found in wheat, garlic, onion and some vegetables. People can't fully digest them, so they reach the large intestine, where gut bacteria ferment them. Read more about high FODMAP foods to avoid with IBS.

Lower-FODMAP swaps

More vegetables

Common questions

Are onions low FODMAP?

Onions are high FODMAP and are usually limited during the elimination phase. They contain fructans.

Which FODMAPs are in onions?

Onions contain fructans. Fructans are chains of fructose found in wheat, garlic, onion and some vegetables. People can't fully digest them, so they reach the large intestine, where gut bacteria ferment them.

Can I have onions during the low FODMAP elimination phase?

It's usually best left out during elimination and tested later, during reintroduction.

What can I use instead of onions?

Lower-FODMAP options include scallion greens, chives and leek leaves.

How do I test onions during reintroduction?

Onions belong with the fructans group, which is often tested with regular bread or pasta. Test one group at a time, starting small and increasing over a few days, and note how you feel.

Onions in our guides

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