Bean
Food · Legume · Food, Typed Supps
Dried, fresh and canned beans look like different foods but mostly differ in how much water they hold.
Stage by stage
- Intake (Cooking softens and detoxifies): Boiling softens the seed coat and destroys the lectins that make undercooked kidney beans unsafe.
- Digestion (Starch released slowly): Starch trapped inside intact cell walls is broken down gradually, producing a low glycaemic response.
- Small intestine (Partial absorption): Protein and most minerals are absorbed; resistant starch and fibre pass through undigested.
- Large intestine (Fermented to short-chain fats): Gut bacteria ferment the resistant starch and soluble fibre into short-chain fatty acids, with gas as the by-product.
Time to effect
- Weeks: Gas and bloating typically settle within two to three weeks as gut bacteria adapt to the fermentable fibre.
Allergens
None of the fourteen major allergens. Derived from what this food is, not from a product label.
Eating patterns
Fits: Vegan, Vegetarian, Pescatarian, Halal, Kosher, Gluten-free.
Satiety
196 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 £2.2 per kg, as a band midpoint rather than a price.
Key nutrients
Nutrition per 100g
- Calories: 311
- Protein: 24.3g
- Carbohydrate: 37g
- of which sugars: 2.7g
- Fat: 2.1g
- of which saturated: 0.3g
- Fibre: 18.6g
- Sodium: 21mg
Food vs. supplement
A fibre supplement delivers one fraction in isolation. Beans deliver fibre, resistant starch, plant protein, folate, potassium and magnesium together, for a few dollars a kilogram, which is why dietary guidelines name legumes rather than fibre capsules.
Kitchen tip
Soak dried beans overnight, discard the water, then boil hard for at least ten minutes before simmering. Rinse canned beans to cut their sodium substantially.
Common myth
"All beans are basically the same, so pick whichever is cheapest." In reality: Soya beans sit apart from the rest: they are an oilseed with several times the fat and far less starch than haricot, kidney or broad beans. Within the starchy beans the swap is fair, but the dried, fresh and canned forms of the same bean differ by weight of water, not by nutrition, so compare them cooked.
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