They are empty calories and serve no nutritional value (not a carb/fat/protein), and they are burned first so you have more of a risk of whatever else you're taking in at the same time or just after will get stored as fats. And I think theres studies going on that say alcohol increase abdominal fat. You shouldn't drink if youre trying to stay fit, period, but if you do it's good to minimalize eating after you consume alcohol because of how it gets prioritized. Needto has a really good post or sticky around here somewhere that lays out the effects of alcohol on diet and exercise.