The problem isn't the amount of calories. Alcohol (ETOH - ethanol - is the type of alcohol in all alcholic drinks - beer, wine, hard alcohol) is a VERY efficient source of energy for your body to use. When you drink, you're body uses the alcohol as fuel, and none of the food you eat. So all the food in your system that hasn't been metabolized is stored as fat.
Ever try working out the morning after drinking? You'll probably find that you will have alot of energy and feel pretty good until the hangover kicks in. I can't tell you how many times I set PR's (personal records) when lifting the morning after heavy drinking. This info came from a former boss of mine. I managed my schools gym while I was in college...my boss was a PHd, and former Olympic skiing and cycling coach.