Miso

Why miso is rated low

Miso is low at about ¾ tablespoon (10g), moderate at larger portions and high at much larger portions. It is soybeans fermented into a paste, usually with a grain such as rice or barley worked in, and fructans are what build as you use more. Fermentation gives miso its flavour but it does not clear out the fructans, so the honest way to treat miso is as a seasoning whose portion you keep an eye on. At about ¾ tablespoon (10g), a spoonful stirred into broth or a glaze, it sits low. The amounts that move it are the heavy-handed ones, the kind that turn it from a background flavour into the main ingredient.

What changes your risk

• How much goes in the pot This is the whole story for miso. About ¾ tablespoon (10g) is low, larger portions are moderate and much larger portions are high, so the difference between a seasoning and a main flavour is the difference between those serves. Stir it in at the end, taste, and stop there rather than adding more out of habit.
• The style of miso Pastes differ in what is blended with the soybeans. Styles with more grain worked in can bring more fructans, and blends with extra ingredients can shift the picture further. Read the ingredient list to know what you are working with.
• Stacking inside the same bowl Miso rarely arrives alone. A soup or marinade that also brings other soy foods, or noodles made from wheat, piles more onto the same meal, and each of those can be low on its own while the bowl as a whole is not. Build the rest of the dish from rice, firm tofu, carrots, bok choy, green beans and the green tops of spring onions.
• What the broth is built on Ready-made soup bases, dashi blends and marinade mixes often carry onion and garlic, and those fructans arrive on top of the miso's own. Read the label, or build the broth yourself and get the savoury depth from garlic-infused oil, ginger and the green tops of spring onions.
• Dissolving it in liquid you then drink Boiling vegetables or legumes in plenty of water and pouring the water away does take some water-soluble FODMAPs with it. Miso soup is the opposite situation: the paste dissolves into broth that goes into the bowl, so nothing is left behind. Heat on its own does not break FODMAPs down.

What else works

If you want savoury depth without leaning on the paste, the most direct swaps are garlic-infused oil for a rounded allium note, a little grated parmesan or another hard cheese for salty umami, and a broth simmered from plain meat, poultry or fish with carrot and the green tops of spring onions rather than a packet base. A pinch of asafoetida cooked in oil gives a similar savoury backbone in marinades and glazes. Firm tofu works alongside all of these when you want the soy character in the bowl without more paste going in. If the recipe truly needs miso, keep it to about ¾ tablespoon (10g) per serve rather than reaching for another fermented soy paste, since a swap made from the same base carries the same load.

How to keep it low

Buy a plain paste with a short ingredient list and check whether a grain is included, since added grain can add to the fructans. Keep the tub in the fridge and take what you need onto a spoon rather than eyeballing it straight into a hot pot, where it is easy to lose track of how much has gone in. Weighing out about ¾ tablespoon (10g) once shows you what a low serve looks like on your own spoon. Dissolve it in a ladle of warm broth first so it disperses evenly and you get full flavour from less paste, and add it off the boil at the end of cooking. When you are making soup for several people, portion the miso for the pot rather than letting everyone stir extra into their own bowl, and serve it with rice and vegetables rather than wheat noodles.

Common questions

how much miso can i have on a low fodmap diet

Miso is low at about ¾ tablespoon (10g), moderate at larger portions and high at much larger portions. Treat it as a flavouring to portion rather than an ingredient to pour.

is miso high in fructans

Not at a spoonful. Fructans are the FODMAP group in miso, and they build with the amount, which is why about ¾ tablespoon (10g) is low while larger portions are moderate and much larger portions are high.

is miso soup low fodmap

It depends on the whole bowl rather than the paste alone. About ¾ tablespoon (10g) of miso is low, but packet soup bases often bring onion and garlic, and wheat noodles add more fructans, so a bowl built that way can add up even when the miso itself is portioned.

does cooking miso reduce the fodmaps

No. Heat does not break FODMAPs down, and in soup the dissolved paste ends up in the broth you drink. Boiling and pouring the water away removes some water-soluble FODMAPs from foods like legumes, but that does not apply to a paste stirred into liquid you are going to eat.