Calories from alcohol affect weight loss just like any other calories. They are considered to be discretionary calories because they are not accompanied by nutrients.  After you’ve eaten all of the food from the food groups that you need in a day, you can spend any calories left on alcohol if you'd like. The guideline for healthy drinking is one drink a day for women and two for men.  One drink is defined as 5 ounces of wine, 12 ounces of beer, or 1.5 ounces of 80-proof distilled spirits.  Also consider that alcohol suppresses inhibition, which may lead to overeating especially in social settings.