I was a 30-32 waist when I was about 18 or 19. I also weighed 135-150 lbs. If I get down to 160 now I look like I'm a terminal cancer patient. Currently about 170.
Trying, of course, to get down to 160. OK, so maybe if I did get to 160 I'd fit in 32 sized jeans. But I'd never buy a pair that size, because one bag of friggin Doritos and they'd never fit again.