Watch out, though, if you're in ketosis your tolerance is MUCH lower than it was before. I found this out the hard way. Take it slow and alternate with Perrier or something if you can. For me, oddly, hard liquor (caipirinhas) didn't hurt me but wine (prosecco) kicked my butt in a really unpleasant way.

And do NOT skip lunch to save up carbs... Atkins lightweightness + empty stomach = trouble.