General

Well, basically what you're gonna have to do is make him understand that it's not something that can be changed and that even though he doesn't have to understand why you like fat chicks, he'll have to accept that it's who you are.

If he thinks you need therapy and that this can be "fixed", then it's going to be tough, and it might take a while. But you're 22, you're an adult and in charge of your own life; and if you don't already have your own place, it's likely you will soon, which should help any anxiety you might experience regarding this.

My advice is to let it be for a bit- don't bring it up unless he does. When you talk about it, don't be hostile, but don't be apologetic. There's no reason to be sorry for being you. And one thing that I think might help him understand how basic it is and how you likely can't change it is to ask him whether he prefers, say, blondes or brunettes, and then note that it's kinda like that, only with body type instead of hair color.

Bottom line is that he doesn't need to understand it or even like it (though that'd be nice), he just needs to accept it, and I'd think that as a parent he loves you enough to make an effort... even if that takes a little time.

A long time ago, when my mom first found out, her immediate reaction was that I must have really low self esteem because subconsciously, I must believe that that's the only type of woman who'd accept me. Yeah, my mom is awesome. When she says something insensitive, it's insulting on at least 3 levels. Anyway, after that awkward conversation, she decided to just leave well enough alone and accept it. She told me that I could fall in love with trailer trash if I wanted to, and if it made me happy, she'd be happy for me. She's not a bad person, she just has no idea what is or isn't appropriate to say.

Why exactly does Dad need to accept it? (Please list any and all reasons)