Drinking alcohol, Diets Cokes, etc

Are you allowed to drink hard liquor when you get the sleeve done?
I am jsut getting the ball started with finding a Dr.... saving up the money to have it done. I should be able to pay for it no later than Maybe April.
I think I can give up any food, but its the Diet Cokes, Bourbon, and Lemon Berry Slushes from Sonic I think I will have the most trouble with.
Let me know what you think