This is totally without merit. I think a couple of guys got a grant to do a "study" on this and just bought a ton of beer with the ca$h!
Everyone knows beer makes you fat primarily because of the carbohydrates, not the alcohol. It is untrue that all alcohol will make you fat. Alcohol is empty calories, true, and while empty calories can turn into fat, it's not the case with alcohol carbs like in gin or vodka, which are different than the types of carbs found in beer.
In addition to the beer itself, many of the foods eaten while drinking beer contribute to an extended belly: pretzels, pizza, nachos, etc. also very heavy carb foods.