The Math Behind Losing Weight (Why Daily Counting Breaks Down) Weight loss is not a daily event. It is an annual calorie equation. Roughly, maintaining 1 kg of body weight requires about 10,000 calories per year. A person weighing 120 kg operates on a much larger calorie economy than someone at 80 kg. To lose 40 kg and maintain it, the body must adapt to a yearly deficit of approxim... https://www.freedomfromdiabetes.org/blog/post/why-daily-calorie-counting-fails/5056