In my experience having an alcoholic drink after bypass is not too bad. I was nearly 6 months post op before I did drink. I have only had a drink 4 times so far, lol. I found that I get tipsy (and it is only tipsy) very quickly, within a couple of minutes, but the feeling doesn't last for more than an hour and then I'm sober again. On the one occasion I had more than one (3) drink over a period of some hours it was unpleasant because the accelerated reaction meant that i had a horrible hangover before I even got home! Lucky I was a moderate drinker before, so I dont often miss it.
I do wish pubs would have NAS available, it would save me a lot of calories.