It's not so much weight as age. Typically your metabolism slows down a few years after maturity, since it no longer needs to burn lots of calories for a growing (upwards, lol) body. This tends to mean early-to-mid 20s, as evidenced by the fact I weighed 150 at 25, and without changing diet or lifestyle dramatically now weigh 250 at 45 without trying ...
11 years
