Obviously, if you can eat properly on the weekends as well as the week days you are going to have superior results. However, I generally allow myself at least a couple cheat meals over the course of the weekend. I don't sweat it.. I just hop back on the plan as soon as Monday rolls around. I've found that it keeps me a lot more focused... ESPECIALLY if i eat 3 or 4 really fatty, garbage meals... I don't want to even THINK about touching the stuff for another week.
Sometimes i think back to how many weekends I pissed away with alcohol and stuff, and wonder how much better my gains would have been if I had been more responsible.
I don't think drinking every once in a while is going to effect you too much... Unless you are looking for extreme results...
Its like everybody says... it depends how badly you want to have the extreme body... Its not easy... and you do have to make sacrifices...
Usually Partying is one of the first things that needs to go...
You have to weigh out the benefits as to what you want more...