I am questioning the value of diet and exercise. Thermodynamics is technically true but useless, barring the application of physical constraint or inhuman willpower to artificially produce famine conditions and keep them in place permanently. You, clearly, are one of the metabolically privileged, so let me assure you that I could try exactly the same things you do to control your weight and fail. My fat cells would keep the energy that yours release; a skipped meal you wouldn't notice would have me dizzy when I stand up; exercise that grows your muscle mass would do nothing for mine.