I knew a girl who faked having HIV in high school. She lied about having it, how she contracted it, how she was paying for the medicine, etc. I was the only one who called her out on her bullshit, and I lost all of our mutual friends. "How could you be so mean to her?!" "She's sick, why would she lie about that?" About 3 or so years after we all graduated, they all slowly got back into contact with me, mostly via Facebook, apologizing and admitting that she was a lying piece of shit and they'd gotten tired of it. And how they should have listened to me in the first place. And yes, of course, she was fat. Probably 280 at around 5'6". She always claimed to be about 150. She also lied about being addicted to coke for 3 months, "baking" meth in her mom's basement, and she was every single sexuality and sexual identity under the sun, and this was back in maybe 2004-2008, before the whole Tumblr identities thing really became a thing.  They do it for attention, so people will feel sorry for them and dote on them. It's a weird sort of "grass is greener on the wrong side of the tracks" kinda thing. Most people I've known who do this come from decent homes, caring parents, decent money and middle-class standing. They want to be somehow "broken" in order to seem more interesting, "darker" or "edgier", that kinda thing. It's fucking stupid.