I gained when I quit, but only because I was eating crappy. And when I drank, it was getting bad. Lots of vodka, and lots of fast food. ( Some days I wasn't even sure how I drove to get it, but that is another story)
I was probably at my heaviest when my drinking got the worse it ever was, so to tack on an extra tonnage when drinking and eating poorly didn't help.
I have never been a real exercise fan, wouldn't consider myself "unfit" before I started drinking, but now, since I am heavy, I am not as active as I once was. Mostly because of my weight, but I also developed some health issues as a result of heavy drinking, low vitamins, dehydration, etc.