My g/f keeps complaining about being supposedly "fat", "ugly", and "stupid"?!?

[KinnyChan]

She keeps thinking she's fat. (No, she's not anorexic)

She keeps thinking she's ugly.
And she keeps thinking she's stupid.
And she moans about it. Often.
Even though she's definitely not fat or ugly and she's in fact one of the smartest in her grade.

She complains about that stuff almost every other time we see each other and it's really annoying. I mean, it's KIND OF endearing, but seriously...
How can I explain to her a way that will actually make her see the truth?
The "stupid" part is sort of joking, but she's serious about the "fat" part. (No, she's not anorexic)

[kman]

Ugh. Dump her.