Riku, your friend, does she know you've also got a psychological eating disorder?
If not, perhaps mention to her that you do, and more often than not even strict anorexics become a bit more tactful. Truth is, we are experts in not just the obsession with food and intake, but experts in detracting if food is the topic at hand!
My two pennies? More than likely she's EXPECTING fixation on the intake/,outgoing foodwise, as anorexics thrive off "oh you're getting gaunt!" or "oh, you poor thing, you look ill"; she was more likely digging for a response like "Are you kidding, you're still wafer thin!!"
Don't say that though. You're feeding the bad part. Mention you're also a bit discomforted by all this talk of food, and it as a topic is -no pun intended- off the table!