so... I 'm supposed to say what?

I have this coworker who is unintentionally very funny. And occassionally somewhat annoying. Sometimes I want to just stare at her like she's from Mars. Mostly because I just don't know how to respond. I really have to post the following moment so you can fully understand.

Me: (unwrapping a burger which is supposed to be meatless, discovering a grayish beef patty and trying to pull it out of the burger) oh.
Her: Just eat it. Come on.
Me: Nope, It will just make me sick. (extracting the patty and putting it in the trash)
Her: Oh, come on you can eat it.
Me: I haven't eaten meat in about 3 years. If I try now I'll just throw up. It's not pretty. It's fine, I'll just scrape it off.
Her: You know they just did this study on diet. They tested people who ate all meat against people who ate no meat. The meat eaters did 20% better on tests. So I'm smarter since I eat meat.

I ask you, what is the appropriate reply for that?
And who is this they?