I got down to 200lbs! Then I ate a whole pork shoulder. With the skin. I think my body wants me to stay between 11 and 14 percent body fat. Soldiers traditionally kept in that range in case they needed the extra energy (marches and extended battles) and I come from a long line of them, so it's probably built in by now.
In all of the universe there is only one person with your exact charateristics. Just like there is only one person with everybody else's characteristics. Effectively, your uniqueness makes you pretty average.