I think my metabolism is a little low. "Starvation mode" is a myth. Your body can't hang on to fat when you eat very few calories. But adaptive thermogenesis is real (Google it and you will find a lot of peer reviewed papers and studies); people who lose a lot to get down to a healthy weight burn less calories than people who were always that weight. It's only 10% or so, but if base + exercise is around 2000, that's 200 calories. Not everyone is exactly 10%; that's an example. I am pretty fit now. I don't look like a body builder or a linebacker but it is obvious I have been exercising.