I seem to have the metabolism of a runner, in spite of being amazingly sedentary.
I envy you. In addition to getting older, I also take some meds that are known for slowing metabolism. Having said that, I've lost about 25-30 pounds this year, and I'm down to about 220-225. I've eaten more healthy in the last 6 months than I have my entire life, and it's actually not bad.