Total Daily Energy Expenditure — the total calories you burn in 24 hours, including your resting metabolism plus all physical activity. Eating at TDEE maintains your current weight.

Estimates are typically within ±10–15% of true expenditure. Use the result as a starting point, then adjust by ±200 kcal based on 2–3 weeks of actual weight trend.

Most people overestimate their activity. If unsure, choose one level lower than feels right. "Sedentary" covers desk jobs with walks of under 30 minutes/day. "Lightly active" covers 1–3 workouts per week.

Yes — a deficit of 300–500 kcal/day produces roughly 0.3–0.5 kg of fat loss per week, which is sustainable. Deficits larger than 1,000 kcal/day risk muscle loss and metabolic slowdown.