Kale

Why kale is rated low

Kale is a leafy green carrying very little fermentable carbohydrate, and the published data records no FODMAP subgroup against it at all. That puts it at low at a Small serving. It moves to moderate at a Large serving, not because of one particular carbohydrate group but because the overall FODMAP load rises with the sheer amount of leaf on the plate. Kale is in the inferred tier, so its level is estimated from the composition of the leaf rather than taken from a measured serving trial, which is why the ladder is written as Small serving and Large serving with no weight given.

What changes your risk

• Serving size, and the shrinkage trap Kale is low at a Small serving and moderate at a Large serving. Raw kale wilts down hard, so what looks modest in the pan at the end can be far more leaf than it appears. Judge the serving by how much kale went in, not by what comes out.
• Kale chips and green smoothies Drying kale into chips removes the water and concentrates everything left behind, so a bowl of chips represents a great deal of leaf. A green smoothie does something similar by packing raw kale that would read as a Large serving into one glass. Both are easy ways to arrive at the moderate rung without noticing.
• What it is cooked with Sauteed kale is very often sauteed with garlic and onion, and kale soup is usually built on a stock cube. Garlic-infused oil carries that flavour with none of the fructans, because fructans are water-soluble and do not dissolve into oil, as long as no solid pieces are left sitting in it. Chives and the green tops of spring onions do the rest of the work.
• Stacking across the plate No subgroup is recorded for kale, so the thing to watch is the total FODMAP load of the whole meal rather than one carbohydrate group. A big bowl of kale next to several other vegetables adds up even when each part was counted on its own.
• Heat is not the lever people think it is Steaming, roasting, sauteing, freezing or massaging raw kale leaves the FODMAP content exactly where it was. Heat does not break FODMAPs down. Boiling in plenty of water and pouring the water away can carry some water-soluble FODMAPs out with the liquid, but that is the water taking them, not the cooking destroying them.

What else works

Kale is already low at a Small serving, so the useful comparison is the rest of the greens aisle. Baby spinach and bok choy do the same job raw or cooked, and green beans, zucchini, carrot, cucumber and bell pepper round out a plate without adding a different problem. The lookalike to keep clear of is cauliflower, which is a very different food despite living one shelf over, and leek bulb and onion are never the stand-in for a green. Watch bagged superfood or slaw mixes too, since they often combine kale with other vegetables and a dressing sachet, so what is in the bag is no longer just kale.

How to keep it low

Buy kale bunched rather than pre-dressed, and strip the leaves off the thick central stems before cooking, since the stems are what make kale chewy rather than what makes it worth eating. Stored dry, wrapped loosely in a clean tea towel in the fridge drawer, it holds for several days. For salads, massage the torn leaves with olive oil and a little salt until they darken and soften. For a hot side, cook it in garlic-infused oil with chives rather than garlic cloves, and finish with lemon. If you are buying it pre-chopped in a bag, check that the ingredients are kale and nothing else, because onion and dressing sachets turn up in mixes more often than people expect.

Common questions

is kale low fodmap

Yes at a Small serving. The data records it as moderate at a Large serving, so the amount on the plate is what matters rather than the kale itself.

how much kale can you eat on a low fodmap diet

The ladder is qualitative rather than measured: kale is low at a Small serving and moderate at a Large serving. Because cooked kale shrinks so much, judging by the raw amount is the more reliable habit.

are kale chips low fodmap

Drying removes the water and concentrates what is left, so a bowl of chips represents far more leaf than the same kale eaten fresh, which makes it easy to reach the Large serving rung where the data says moderate.

can i put kale in a green smoothie

A smoothie packs a lot of raw leaf into one glass, which can amount to a Large serving where kale is recorded as moderate. Keeping kale as one part of the blend rather than the bulk of it keeps it nearer the Small serving end.