Flour
Food · Grain · Food, Typed Supps
Flours differ by how much protein they hold and whether the bran is still in them.
Stage by stage
- Intake (Cooked starch softens): Gelatinised starch from baking or boiling is exposed to salivary amylase as it is chewed.
- Digestion (Starch to glucose): Amylase breaks starch into glucose; finely milled white flour is broken down faster than coarse wholemeal.
- Bloodstream (Glucose absorbed): Glucose enters the blood. Bran, where present, passes through undigested.
- Longer term (Fibre fermented): Gut bacteria ferment bran fibre into short-chain fatty acids, the main difference between wholemeal and white.
Time to effect
- Weeks: Substituting wholemeal for white flour shifts fibre intake and bowel habit within one to two weeks.
Allergens
Contains: Gluten. Derived from what this food is, not from a product label.
Eating patterns
Fits: Vegan, Vegetarian, Pescatarian, Halal, Kosher. Depends on the product: Low-FODMAP.
Satiety
169 on the satiety index, where white bread is 100 — high. Modelled from the Holt et al. (1995) measurements.
Environmental footprint
1.6 kg CO2e and 648 litres of freshwater per kg, matched to "Wheat & rye" in Poore & Nemecek (2018), Science 360.
Cost band
Cheap — roughly £2 per kg, as a band midpoint rather than a price.
Key nutrients
Nutrition per 100g
- Calories: 322
- Protein: 11.4g
- Carbohydrate: 54.9g
- of which sugars: 1.4g
- Fat: 2.3g
- of which saturated: 0.3g
- Fibre: 17.3g
- Sodium: 4mg
Food vs. supplement
Not a supplement category. The comparison that matters is between flours: wholemeal delivers fibre with the grain's minerals attached, while fortified white flour delivers specific added nutrients — thiamin, folate, and in some brands iron and zinc — without the bran.
Kitchen tip
Use bread flour where you want stretch and structure, plain flour where you want tenderness. Wholemeal absorbs more water than white, so a straight substitution gives a dry dough unless the liquid goes up.
Common myth
“Spelt and rye are gentler, low-gluten alternatives to wheat.” In reality: Both contain gluten. Spelt is a wheat species and rye's gluten is simply weaker at building structure. Neither is safe in coeliac disease. The genuinely gluten-free flours in this family are rice, chickpea, soy, hemp, arrowroot and maize cornflour.
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