1200kcal is plenty.  Obesity doesn't mean your body requires more calories per day.  Medical studies have shown that the RMR of fats is not higher than humans.  The primary contributors to RMR are organs, followed by muscles. Fatty mass does not significantly add to RMR. Cunningham, John J. "Body composition as a determinant of energy expenditure: a synthetic review and a proposed general prediction equation." The American journal of clinical nutrition 54, no. 6 (1991): 963-969. An independent contribution by FM to the prediction of either REE or TDEE is not supported Note: in morbidly obese women FM does contribute, but only by a few hundred kcal per day.