How do I not have an eating disorder?

On Sunday night I was over at the parental units' house for tea. It was just the three of us having a grand ol' time. I was conscious at the time of how nice it was to just be shootin' the shit with them, as opposed to the usual arguments/negativity I experienced while growing up. I think they are finally beginning to relax and enjoy life now that the kids are out of the house.

So at one point I was walking through the kitchen while father was doing dishes and he looked at my pants (brand new super skinny dark jeans I got on e-bay for a fraction of the store price). I know he's a fan of dark wash, and anything skin-tight (he was at his prime in the 70's... think Saturday Night Fever).

Exhibit "A":

The following conversation took place:

Me: "oh, you like these new jeans?"

Father: "Yeah... You've put on some weight, haven't you?"

Jezuz effing chrrrrist.

Me: "Yes." [walks away in fiery rage]

What Me really should have said: Yes, I have put on some weight in the past several months, 4 pounds to be precise. The weight is attributable to two pregnancies which ended in miscarriage. You would not know anything about that because you are a dick in every sense of the word. You do not know any of these facts because I do not tell you, as I am aware of your judgmental nature, and realize it is better to take an uniformed insult once in a while than have you know my business. I should point out, however, that I was actually underweight before, and am now at an ideal BMI for my height. You, however, have a beer gut and will likely die prematurely due to heart failure, or worse, have a stroke which incapacitates you, requiring your family members to care for you like a child. So when I'm spoon-feeding you in your wheelchair, don't be surprised if a little cyanide gets into your applesauce.