JK Rowling has criticised models whose "only function in the world appears to be supporting the trade in overpriced handbags and rat-sized dogs."
JK Rowling thinks models are "empty-headed, emaciated clones"
The Harry Potter author said her daughters, Mackenzie, one, and Jessica, 12, would not be "empty-headed, self-obsessed, emaciated clones."
Writing on her personal website the Edinburgh-based author hit out at those who promote thinness.
She said she was sick of seeing models who suffer from eating disorders.
She said: "It started in the car on the way to Leavesden film studios.
"I whiled away part of the journey reading a magazine that featured several glossy photographs of a very young woman who is either seriously ill or suffering from an eating disorder (which is, of course, the same thing); anyway, there is no other explanation for the shape of her body.
"She can talk about eating absolutely loads, being terribly busy and having the world's fastest metabolism until her tongue drops off (hooray! Another couple of ounces gone!), but her concave stomach, protruding ribs and stick-like arms tell a different story.
"This girl needs help, but, the world being what it is, they're sticking her on magazine covers instead.
"All this passed through my mind as I read the interview, then I threw the horrible thing aside."
She added that some people at the recent British Book Awards were more interested in her weight than her latest book.
"So the issue of size and women was weighing on my mind as I flew home to Edinburgh the next day," she said.
"I've got two daughters who will have to make their way in this skinny-obsessed world, and it worries me, because I don't want them to be empty-headed, self-obsessed, emaciated clones; I'd rather they were independent, interesting, idealistic, kind, opinionated, original, funny a thousand things, before 'thin'."