Calories consumed in excess of those with which the body needs to be provided to maintain its weight are normally stored as fat and the body gains weight  Alcoholic beverages are laden with calories
However, those people who regularly drink two or three alcoholic beverages a day and thereby exceed the caloric intake necessary to maintain their weight do not in general gain weight
Excess calories consumed by people who regularly drink two or three alcoholic beverages a day tend to be dissipated as heat.