Fennel

Why fennel is rated high

Fennel bulb is high FODMAP because of fructans, the only subgroup the data attributes to it. The published serving data covers one amount, 1 cup sliced (75g), and fennel is high there. No smaller serving has been tested, so there is no published portion that falls into the low range. Fructans are not broken down by heat, so slow braised fennel that has gone sweet and soft in the pan carries the same fructans as the raw bulb it started as, and the softer it cooks the more of it fits on a plate.

What changes your risk

• Serving size 1 cup sliced (75g) is the only tested amount and it is high. Nothing below it has been tested, so no lighter portion can be named as low.
• Shaved and braised forms fit more in Fennel shaved thin for a salad or braised down to half its volume takes up far less room than raw wedges, so the amount on the plate climbs without looking like it has.
• Cooking does not break fructans down Roasting, grilling and pan frying leave the fructans exactly where they were. Boiling in plenty of water and pouring the water away does move some water soluble FODMAPs out of a vegetable, which is a separate effect, but no lower serving of fennel has been tested, so this is not a route to a low portion.
• Stacking with other fructan foods Fructans are the most commonly stacked subgroup there is. Fennel alongside onion, garlic, wheat pasta or bread, or globe artichoke in the same meal loads the same subgroup several times over.
• Hidden in the dish, not just the plate Fennel is often braised into sauces, sausage stuffings, fish stews and slow cooked pork, where it dissolves into the dish. The fructans stay in the sauce after the visible pieces have been removed.

Swaps

For the roasted or braised vegetable role fennel usually plays, zucchini, bell pepper, carrots, green beans and bok choy all caramelise well and hold their shape in a slow cooked dish. For the crunch of a shaved fennel salad, thin cucumber slices, carrot ribbons and sliced bok choy stems give the same texture, with chives or the green tops of spring onions for a fresh bite. The one thing none of them replaces is the anise flavour, and the published serving data does not offer a tested low FODMAP vegetable that carries it, so it is more honest to build the dish around a different flavour than to reach for a substitute that has not been tested.

How to lower the load

Fennel bulb is the part covered by the tested serving, and it is most often bought whole, which encourages using the entire bulb in one dish, so plan the meal around another vegetable rather than buying a bulb and trying to portion it. In restaurants it shows up in fish stews, Italian sausage dishes, roasted vegetable sides and citrus salads, and it is frequently listed only in the dish description, so it is worth naming when asking. At home, if the rest of the household eats it, keep the braising liquid separate, because a sauce that has had fennel cooked in it carries the fructans that came out of it.

Common questions

is fennel low fodmap

No. Fennel is high FODMAP at 1 cup sliced (75g), the only serving in the published data, and no smaller amount has been tested.

is fennel high in fructans

Yes. Fructans are the subgroup behind the high rating at 1 cup sliced (75g), and they are the only subgroup the data flags for fennel.

does cooking fennel make it low fodmap

No. Fructans are not destroyed by heat, so roasted or braised fennel carries what the raw bulb carried, and braising it into a sauce moves those fructans into the sauce.

can i eat fennel during the elimination phase

Fennel is high at its tested serving of 1 cup sliced (75g), so it is normally left out during the strict phase. Reintroduction is worked through with a dietitian, and tolerance varies from person to person.