Not sure if its common or not, but I would often skip lunch and/or dinner on a daily basis to fill up on alcohol, and then drink some Gatorade the next morning for my first drink...I started eating again regularly now and feel much much better!! its almost like you forget how much energy you can have at one point and time...I wouldn't worry about gaining weight...or at least not right now. If you become healthy, your body can start to focus on metabolizing food/nutrients instead of constantly trying to process the alcohol in your system.