Fried Onion

Why fried onion is rated high

Fried onion is high FODMAP, and the onion itself is the reason. Onion is rich in fructans, and frying does nothing to remove them. Heat does not break fructans down, and because fried onion loses much of its water in the pan, the crisp pieces are concentrated onion. The rating is estimated from what the food is made of rather than a measured serving, and it reads HIGH at Any typical portion. There is no lower rung to fall back on, so no serving size turns it into a safe topping. The useful move is a swap that delivers the same savoury, golden flavour.

What changes your risk

• No lower rung The estimate puts fried onion at HIGH for Any typical portion, so using less of it is not a strategy here.
• Frying concentrates, it does not cleanse Frying drives water out, so crisp onion packs more onion into less space. Heat does not destroy fructans, so they stay in every crunchy piece.
• The oil versus the pieces Fructans are water-soluble and do not dissolve into oil. That is why oil infused with onion or garlic, with every solid piece removed, carries the flavour without the fructans. The crispy bits themselves are where the fructans sit.
• Hidden onion on the label Onion powder, onion salt, vegetable stock cubes, gravy mixes and most spice blends and seasoning rubs are the same problem in another form, as are jars of ready-made crispy onion and fried shallot toppings.
• Stacking with other fructans Fried onion on a burger in an ordinary wheat bun, or scattered over a curry with a garlic-heavy sauce, piles more fructans onto a food that is already high.

Swaps

The substitution that actually works is garlic-infused or onion-infused oil: fructans do not dissolve into oil, so the flavour comes through with none of the fructans, as long as no solid pieces are left in the bottle. Cook your base in it wherever a recipe starts with frying onion. For the crunchy topping role, slice the green tops of spring onions or the green leaves of leek and fry them until golden and crisp. Chives add a fresh onion note scattered on at the end, and asafoetida, fried briefly in oil, gives curries and stir-fries a savoury, oniony depth (choose a gluten free one, since many are cut with wheat flour). Fried shallots, fried garlic, the white part of spring onion and the white of leek are not swaps. They are the same problem.

How to lower the load

To make a crispy topping at home, slice spring onion greens or leek leaves thin, pat them completely dry, and fry in shallow oil until golden, then drain on paper towel. The oil can be kept for cooking, since only low FODMAP greens were in it. Read the label on anything sold as a crispy topping, burger seasoning or stock, because onion powder and dried onion turn up there often. When eating out, burgers, hot dogs and many noodle and rice dishes are finished with fried onion or fried shallot, so ask for it to be left off rather than picking it out, and check whether onion is also cooked into the dish itself.

Common questions

is fried onion low fodmap

No. Fried onion is high FODMAP because onion is rich in fructans and frying does not remove them. Its rating is estimated from what it is made of, and it reads HIGH at Any typical portion.

does frying onion reduce fructans

No. Heat does not break fructans down, and frying drives water out, so crisp fried onion is concentrated onion. Fructans also do not dissolve into oil, which is why strained infused oil is a different story from the onion pieces.

can you have fried onion on the elimination phase

It is best left out during the elimination phase, since no serving comes in lower than HIGH. Garlic-infused oil, chives and crisp-fried spring onion greens fill the gap.

what can i use instead of crispy fried onions

Fry thinly sliced green tops of spring onions or green leek leaves until golden and crisp. The green parts are the low FODMAP choice, unlike the white bulb, and they give a similar savoury crunch.