Set a daily calorie deficit for weight loss.
A calorie deficit is the gap between what you burn and what you eat, and it converts to weight at roughly 7,700 kcal per kilogram of body mass. Half a kilogram a week therefore needs about 550 kcal a day below maintenance. Expressing that as a percentage of maintenance is more useful than the raw number, because the same 550 kcal is a modest fifteen percent for someone burning 3,600 and an aggressive thirty for someone burning 1,800. The convention is fifteen to twenty-five percent: enough to make visible progress, small enough to preserve muscle, training quality and adherence. This also enforces a floor, because a deficit that pushes intake below roughly 1,500 kcal for men or 1,200 for women makes micronutrient adequacy difficult and belongs under clinical supervision rather than a calculator.
Daily deficit and intake target
Weekly deficit = target weekly loss x 7700; daily deficit = weekly deficit / 7, capped so that intake stays above 1,500 kcal (male) or 1,200 kcal (female); daily target = maintenance - daily deficit
General educational estimates, not medical or dietetic advice. Calorie needs vary with health conditions, medication, pregnancy and body composition, and rapid or prolonged restriction carries real risks. Consult a doctor or registered dietitian before starting a weight-loss programme.
Because tolerance scales with size. A 500 kcal deficit is comfortable for a large, active person and severe for a small, sedentary one. Fifteen to twenty-five percent of maintenance travels across body sizes in a way that a fixed number does not.
Because the requested rate would have pushed intake below the floor where meeting protein and micronutrient needs becomes difficult. Faster loss at that point means losing more muscle, not more fat — and it belongs under medical supervision.
No. It describes the first months well, then adaptation intervenes: maintenance falls as you get lighter and non-exercise movement declines, so the same intake produces slower loss. Recalculate maintenance every four to five kilograms.