Lupin

Food · Legume · Food, Typed Supps

A bean that is mostly fibre and protein, with hardly any starch in it.

Stage by stage

Intake (Mouth): Eaten as flour, flakes or soaked splits — the whole seed is too hard to eat without preparation.
Stomach (Stomach): Little starch is present, so there is far less to convert to glucose than in any other legume.
Small intestine (Small intestine): Protein, folate, magnesium and non-heme iron are absorbed; the protein is limiting in methionine.
Large intestine (Colon): The very large fibre fraction, mostly from the hull, ferments slowly in the colon.

Time to effect

Days: Stool bulk and regularity respond within 1 to 3 days; the reduced glycaemic response appears in the first meal it is used in.

Allergens

Contains: Lupin. Derived from what this food is, not from a product label.

Eating patterns

Fits: Vegan, Vegetarian, Pescatarian, Halal, Kosher, Gluten-free. Depends on the product: Keto, Low-FODMAP.

Satiety

281 on the satiety index, where white bread is 100 — very high. Modelled from the Holt et al. (1995) measurements.

Environmental footprint

1 kg CO2e and 397 litres of freshwater per kg, matched to "Peas" in Poore & Nemecek (2018), Science 360.

Cost band

Cheap — roughly £2.5 per kg, as a band midpoint rather than a price.

Key nutrients

Dietary fibre
Protein
Folate
Magnesium

Nutrition per 100g

Calories: 283
Protein: 28.6g
Carbohydrate: 7.4g
of which sugars: 2.3g
Fat: 6.5g
of which saturated: 0.9g
Fibre: 41.5g
Sodium: 50mg

Food vs. supplement

As a fibre source it does something a psyllium or inulin sachet does not: it brings 28.6g of protein and 350mcg of folate per 100g along with the fibre, and it goes into food rather than beside it. What it will not do is match an isolated soluble-fibre supplement for viscosity-driven cholesterol lowering, since lupin fibre is largely insoluble cell wall material.

Kitchen tip

Substituting lupin flour for 10 to 20% of the wheat flour in a bread or pancake recipe raises the fibre and protein without wrecking the texture; beyond that the lack of gluten and the strong flavour start to show. Whole seeds need long soaking with changes of water, which is why flakes and splits dominate retail.

Common myth

"Lupin flour is just another low-carb grain flour." In reality: It is a legume, and a declared allergen in Australia with real cross-reactivity in peanut-allergic people. Its macronutrient profile is also unlike any grain flour — almost no starch, close to half fibre in the whole seed.