An eating disorder? I think that's taking it a bit too far. In my culture, smacking is considered bad manners and rude. It's a noisy way to eat your food, it disturbs the other person trying to eat their food, and no matter how good the food taste, it's really not necessary to eat so loudly! Don't get me started on talking about "disorders" and "addictions" and "diseases". I think some unethical people who are medical professionals only call something a "sickness" or an "illness" so that they can make money charging you for the treatment of something you can control with your own will power, on your own.