alcohol has several negative effects for gaining muscle and fat loss. It sounds like you asking if it will make you fat. so ill cover some of that aspect, alcohol will lower your protein absorption, to what extent depends on how much you drink. beer has alot of calories which needs to be taken into account with the rest of your diet, in the end it's all realitive if it matters or not depends on what the rest of your diet and exercie looks like, if you've made changes to include beer and those exra calories then your a-o-k. is that making sence?
generaly there is room for 3-4 beers a week and it wont prevent you from looseing fat, but it will hinder your progress.