Olive Oil

Why olive oil is rated low

Olive oil sits low, and the data gives it a single rung: Any typical portion. That rating is inferred, meaning it is estimated from what olive oil is made of rather than measured at a weighed serving in the lab. Pressed oil is fat with essentially no carbohydrate left in it, and no FODMAP subgroup is recorded for it, so there is nothing in the oil itself for gut bacteria to ferment. Because the ladder has one rung, there is no point further up where the oil turns the way a fruit or a legume does. What changes is almost always the company it keeps: the dressing, the pesto or the pan sauce it ends up in.

What changes your risk

• Serving size Low here means low at Any typical portion, which is the only rung the data gives. Amounts beyond a normal cooking or dressing portion have not been tested, and a low rating is never the same as unlimited.
• Solids left in the bottle Oil is the gentle part. Once whole garlic cloves or onion pieces have been steeped in it and left sitting there, the bottle is no longer just oil. A properly strained infused oil with nothing solid floating in it keeps the flavour and leaves the troublesome part of the bulb behind.
• What the oil is sold inside A bottled vinaigrette, a marinade, a tapenade or a seasoning paste is a different product from plain oil, and onion and garlic hide in all of them. The oil's rating does not travel to whatever it has been blended with, so the ingredient list is the thing to read.
• The rest of the plate Olive oil carries no subgroup of its own, so it adds nothing to the meal's running total. The total still matters, because several low servings of other foods eaten together in one sitting can add up, and oil makes those foods easy to eat more of.
• Cooking method Frying, roasting, baking or drizzling it raw makes no difference. Heat does not create or destroy FODMAPs, so the method changes texture and flavour, not the rating.

What else works

Other pure pressed oils sit low for exactly the same reason, so rapeseed oil, sunflower oil, macadamia oil and walnut oil all fill the same job in a pan or over a salad. Garlic-infused olive oil is the genuinely useful one to keep on the counter, because the flavour dissolves into the oil while the garlic solids stay out, as long as the bottle has no pieces left in it. The lookalikes to treat differently are the oil-based products rather than the oils: pesto, aioli, bottled Italian dressings, jarred oils with whole cloves still swimming in them, and house dressings at restaurants, which almost always start with onion or garlic.

How to keep it low

Buy plain oil in a dark bottle and keep it away from the stove, since light and heat dull the flavour long before the bottle is empty. For flavour, build the pan with olive oil plus chives, the green tops of spring onions, leek leaves or a pinch of asafoetida instead of reaching for the bulb, and keep a strained garlic-infused oil for the savoury depth. If you make your own infused oil, strain every piece out rather than leaving cloves in as decoration. Eating out, ask for oil and vinegar on the side rather than the house dressing, and ask for vegetables finished in plain oil rather than in a sauce.

Common questions

is olive oil low fodmap

Yes. Olive oil is rated low, and the data lists it as low at Any typical portion. The rating is estimated from its composition, a pressed oil with essentially no carbohydrate, rather than from a weighed serving.

can i use garlic infused olive oil

Yes, and it is one of the most useful things on a low FODMAP kitchen shelf. The flavour moves into the oil while the parts of the garlic that cause trouble stay in the solids, so the oil has to be fully strained with no pieces left in the bottle.

is extra virgin olive oil different from regular olive oil for fodmaps

No. Both are pure oil with no FODMAP subgroup recorded, and both are rated low at Any typical portion. The difference is in flavour and processing, not in fermentable carbohydrate.

can i have olive oil during the elimination phase

Plain olive oil is fine at Any typical portion. The thing worth checking during elimination is what it has been mixed into, since dressings, marinades and pestos routinely carry onion and garlic.