Health: Starvation on the Web

In fact, like many visitors to pro-ana sites, Lizzy is ambivalent about her "lifestyle choice." "It's a living hell," she says, adding that nothing makes her sadder than healthy young girls entering her site to learn how to starve themselves.

But it's that kind of visit that parents and doctors fear most. Julia Mann, 16, a twelfth- grader in New York who battled anorexia two years ago, says she was lured in by pro-ana websites. "Before, eating disorders started with a diet that spiraled out of control," says Mann, who is researching the effects of such sites for her school science project. "Now it's like, 'I can learn to be anorexic from the Internet.'"

Indeed, for many girls who are struggling with low self-esteem and a negative self-image, the sites can be especially seductive. "Had I not gone to the sites, my weight definitely wouldn't have dropped as low as it did," says Mann, whose 5-ft. 7-in. frame bottomed out at 100 lbs. "The pro-ana sites provide a world that's comforting."

Dr. Richard Kreipe, director of adolescent medicine at the University of Rochester, says it is that sense of belonging that draws many teens to the websites and blogs. If there's one thing teens respond to, it's the rallying voices of other teens, something lacking on sites dedicated to recovery. "Pro-ana sites are much more sophisticated," Dr. Kreipe says.

Whether more inspiring pro-recovery sites could reach teens like Lizzy is an open question. "The anorexic voice inside my head," Lizzy says, "seems to be winning."