In a recent study, a group of subjects had their normal daily caloric intake increased by 25 percent  This increase was entirely in the form of alcohol  Another group of similar subjects had alcohol replace nonalcoholic sources of 25 percent of their normal daily caloric intake
All subjects gained body fat over the course of the study, and the amount of body fat gained was the same for both groups
In the general population, alcohol is the primary cause of gains in body fat.