A Glossary of Nourishment

A Glossary of Nourishment

Terms met in this volume, set down for convenience.

Calorie (kcal) — a unit of energy: the heat needed to raise one kilogram of water by one degree Celsius; the currency in which the body's fuel is counted.

Metabolism — the sum of the chemical reactions by which the body extracts and spends energy.

Basal metabolic rate (BMR) — the energy the body burns at complete rest, simply to stay alive; the largest part of most people's daily expenditure.

Macronutrients — the three energy-yielding classes of food: protein, fat, and carbohydrate.

Micronutrients — vitamins and minerals, required in small amounts, yielding no energy but essential to the body's machinery.

Glycaemic response — the rise in blood glucose after eating a carbohydrate; blunted by fibre, fat, and protein.

Insulin — the hormone that ushers glucose out of the blood and into cells; chronically overworked, it loses its effect (insulin resistance).

Microbiome — the community of microbes, chiefly in the colon, that we feed and that feed us in return.

Short-chain fatty acids (SCFAs) — acetate, propionate, and butyrate; made by gut bacteria fermenting fibre, and a chief fuel of the colon wall.

Fibre — the indigestible parts of plants that feed the microbiome and slow digestion.

Phytochemical — a plant compound (polyphenol, carotenoid, and the like) beyond the classical nutrients, often the source of colour.

Antioxidant — a molecule that neutralises reactive oxygen species; powerful in the test tube, far more complicated in the body.

Hormesis — the principle that a small dose of a mild stress may strengthen where a large dose would harm.

Electrolyte — a dissolved salt (sodium, potassium, and others) that carries the electrical charge nerves and muscles run on.

Ultra-processed food (UPF) — the NOVA classification's fourth group: industrial formulations of substances rarely found in a home kitchen; the century's central nutritional concern.

Food matrix — the whole structure of a food, within which its nutrients behave quite differently from how they behave alone.

Dietary pattern — the whole habitual diet, a more honest unit of study than any single nutrient or food.