2026-09-07

How to swap garlic and onion in low FODMAP cooking

The first “I can’t eat this” for almost everyone on the low FODMAP diet is the flavor base. Onion and garlic are in nearly everything, and they are the two foods richest in fructans. The good news: fructans are not soluble in oil, and that opens the door to nearly all the flavor without the load.

Garlic-infused oil

Gently brown peeled garlic cloves in oil, remove the solids and use the oil. The garlic gives up its aroma to the oil while the fructans stay in the clove, which you discard. It works the same with a drizzle of the oil over the dish at the end.

The green part of spring onion

Onion is red, but the green leaf of spring onion is not: chop it finely as if it were fresh onion, to finish dishes or for gentle sofritos. Not the white part.

Other tricks that work

• Asafoetida (hing) powder: half a pinch into hot oil gives a surprisingly onion-garlic base. Very common in Indian cooking, where it is used precisely for this.
• Dehydrated fried onion, no: it is concentrated fructan. Avoid it.
• Leek, green leaf only, for broths and stews.
• Celery and fennel bulb in moderation: they add body to the base, but they have their own safe serving — check it.

And when you are not the one cooking

In restaurants and ready meals, assume the onion and garlic are inside. This is where the Fodmind label reader makes the difference: photograph the ingredient list and it tells you whether the product fits, without decoding E-numbers by hand.

Elimination is not forever: during reintroduction you test how much fructan you tolerate, and many people go back to eating garlic in small servings. The complete method is explained in the guide.