Nuts/Seeds and FODMAPs: 34 foods rated

Beans are high here from GOS - raffinose, stachyose and verbascose - which no human enzyme can split. That is why beans affect everyone and not only the sensitive, and why the fix is mechanical rather than personal: soak, discard the water, cook in fresh water, discard that too.

Broad beans are a pulse, and pulses are the galacto-oligosaccharide group - chains humans have no enzyme to split, so they arrive in the colon intact and ferment. Soaking and discarding the water removes part of them; canned and rinsed measures lower than dried and boiled at home.

• Tuck C et al., J Hum Nutr Diet 31 (2018), FODMAP content of common plant-based and processed foods

Cashews are one of the two nuts the low-FODMAP tables leave out altogether rather than limit — the pistachio is the other — and the reason is their galacto-oligosaccharides, the pulse family's sugar in a nut. They also have a route into a diet that beats the portion rule: cashew cream and cashew cheese are eaten by the spoonful as a sauce, where nobody counts out ten nuts. The almond, the walnut and the macadamia are the ones limited by the handful instead.

• Monash University FODMAP composition tables and app, for the serve threshold

Chickpeas are the clearest demonstration of how legumes work here. The GOS dissolve into the soaking and cooking water, so canned chickpeas - drained and rinsed - measure well below the same weight cooked from dried. Aquafaba is that liquid, which means it carries what the chickpeas lost.

Lentils: pulses are high in FODMAPs because of their galacto-oligosaccharides (GOS), which humans have no enzyme to digest. Canned and well-rinsed pulses measure lower than dried ones boiled at home, because the GOS leach into the water - and a small serving is usually tolerated.

Pistachios carry both GOS and fructans, and they are the nut hardest to stop eating because the shelling is part of the pleasure. About fifteen kernels is the threshold, and a bowl of them in the shell disguises how many that is. Almonds, walnuts and macadamias are the lower-FODMAP alternatives.

Red kidney beans must be boiled hard regardless - the raw bean is toxic - and that same vigorous boil in plenty of water is what leaches the GOS. The cooking that safety demands is also the cooking that lowers this level, provided the water is thrown away.

The soya bean carries the highest GOS load of the legumes, which is why the processed forms diverge so widely. Firm tofu is pressed and the whey taken away with the sugars; tempeh is fermented and the mould eats them; soy milk from whole beans keeps them, soy milk from protein isolate does not.

Adzuki beans mostly reach the table as sweetened red bean paste, in mochi, buns and ice cream - which pairs the GOS with a heavy dose of sugar in a portion nobody measures. The plain boiled bean, drained, is the easier form by some distance.

Channa dal is the chickpea hulled and split, and Prichard measured it at 0.13 g of fructans and 0.36 g of galacto-oligosaccharides per 100 g - the smallest of the five foods that survey found to carry anything. Hulling and splitting remove the seed coat, and the long soak that dal needs is normally poured away, which is where water-soluble GOS go. Both figures are per 100 g of the dal itself, not per plate of cooked dal, and a serving of dal is generous.

• Prichard R et al., Int J Food Sci Nutr 67 (2016) 383-390, FODMAP content of foods commonly consumed by ethnic minority groups
• contents per 100 g, not per serve

Green peas carry both GOS and fructans, which is unusual - most legumes bring only the first. They are dose-dependent in a way beans are not: a spoonful in a dish passes, a bowl of them as the vegetable does not.

Split peas are dried peas with the skin removed, and they are eaten as soup - by the bowl, thickened, with the cooking water kept because that is the soup. None of the FODMAP is drained away, which is what separates split pea soup from a rinsed can of chickpeas.

Almonds carry galacto-oligosaccharides, the class the pulses carry, in a quantity a handful does not reach: about ten nuts is the serve the Monash tables leave in. What passes it is the form rather than the nut — ground almond by the cupful in a cake, or a bowl eaten without counting, is several serves at once. Monash gives a threshold per serve, which answers how much rather than how concentrated.

• Monash University FODMAP composition tables and app, for the serve threshold

Psyllium husk is the seed coat of Plantago ovata, and what it is made of settles the answer: a mucilage that swells in water, not the short fermentable chains this axis is about. It is taken by the tablespoon in a large glass of water, which is a small quantity of anything at all. Monash gives a SERVE THRESHOLD, which is a different object from a content. A threshold answers how much, and for grams per hundred the papers are the source, not the app.

• Monash University FODMAP composition tables and app, for the serve threshold

Red lentils are low at half a cup, canned and rinsed, and canning is what makes that possible for a pulse: the galacto-oligosaccharides are water-soluble, so they leach into the brine and go down the sink when you rinse. Dried and boiled at home, the same pulse measures higher unless you throw the cooking water away too.

White beans are low at a small portion, canned and rinsed, and canning is what makes that possible for a pulse: the galacto-oligosaccharides are water-soluble, so they leach into the brine and go down the sink when you rinse. Dried and boiled at home, the same pulse measures higher unless you throw the cooking water away too.