I mostly gave up alcohol because I have a ruined esophagus from years of reflux and alcohol aggravated it no end (would actually make it bleed). Years ago when I was doing straight up Atkins (after induction) I would have a few lite beers on weekends or (more commonly) a rum and diet coke and I still lost fine with ketosis.

But now that I'm mixing in fasting I will only have a beer or two at parties and holidays, that's it. And then, only with food in my system. I would not have alcohol during a fast. I suspect it would basically be ending your fast and I also think that a stomach that's totally empty would be likely to make the effect of alcohol very strong. I've already lost like 90% of my previously superhuman tolerance since I essentially gave up booze so the last thing I want is to drink a beer on a three day fast and end up stumbling around like it's 2am on St. Patrick's day. not that I know what that's like ....