Back in the early 90's I got down to 148 lbs (5'11") - people commented I looked like a cancer patient with a tan - pcad is right!
I found that unsustainable for me. I can sustain 165 (2.3 lb/in) with effort - I was there about 15 months ago but two bad winters set me back (I broke my collar bone last December). As of this AM I was 176lbs (2.47 lb/in) and preparing to do the Whiteface uphill race. I sure wish I was back at 2.3 but I have lost 10lbs since the beginning of April.