Your basal metabolic rate and the calories you burn each day based on your activity, to maintain, lose or gain weight.
How it works
Your basal metabolic rate is what your body burns at rest. Multiplied by your activity level, it gives your total daily energy expenditure: the calories that keep your weight steady.
A deficit of about 500 kcal a day works out to roughly half a kilo a week. We use the Mifflin-St Jeor equation, the most accurate in comparison studies.