Prospective studies, which are generally considered to be more rigorous than cross-sectional studies and which follow groups of people over time, in this case from several months to 20 years, had varied results and produced “no clear picture” of the relationship between alcohol and weight. Several found either no relationship or a negative relationship, at least in women, while others found that men who drank tended to risk becoming obese, especially if they were beer drinkers.
The conclusion from the most recent such studies: While heavy drinkers risked gaining weight, “light to moderate alcohol intake is not associated with weight gain or changes in waist circumference.”
Parker here. “Light to moderate” drinking would be up to one drink a day for women or two a day for men, on average.
You can even lose excess body weight without deleting alcohol from your diet, as in the Ketogenic Mediterranean Diet.