Ethanol, the primary calorie contributor to alcohol intake, provides 7 calories per gram, substantial considering that there are 28 grams in an ounce. So it doesn’t take very many drinks to add up to hundreds of calories. Empty, I don’t know what that means, but a calorie is a calorie. And if you don’t use it, you store it.
With relation to abdominal and intraabdominal fat stores it appears that the anatomical distribution is not related to the source of the calories, but more to genetic and gender distinctions. Men more to abdominal, women more to hips.
Try to convince your client to eliminate alcohol consumption for just one week, keeping all other lifestyle variables in place, and it may be enough to convince him/her that restricting alcohol consumption can have a powerful effect.