I'm not going to eat any food at a dinner party
Why don't you want to eat?
I'm fat and I don't want people to think that I need to eat.
I understand you're self-conscious about your weight. I don't think you should be so overly critical about it that you deny yourself food.
Yeah, I'm not comfortable eating around people.
It sounds like maybe speaking to a professional would be beneficial for you. That way you can get rid of these insecurities and you will be on track to getting back to a healthy weight.