The image of the woman in a bikini is anything but sexy.

Her pelvic bones jut so far from her lower torso that they look like bent elbows. Her actual elbows are the widest part of her arms. And splashed across her concave stomach are the words "Hunger hurts, but starving works."

Just another online posting by someone into "thinspo," short for "thin-spiration," in which people with anorexia, bulimia and other eating disorders (EDs) use the Internet's broad reach to encourage and network about achieving extreme, unhealthy thinness.

"It's appealing to people who are in the throes of their sickness," said Lynn Grefe, president of the National Eating Disorders Association (NEDA). "At that stage, it's like a competition -- 'I can get skinnier than that picture, I can beat her.' "

Thinspo has been an online presence since the dawn of the Internet, but social media are making its effects more pervasive, say treatment and prevention leaders.

NEDA has recently worked with major platforms, including Facebook, Tumblr and Pinterest, to adjust their terms-of-use policies to forbid the promotion of "self-harm" by users.

"Pro-anas" (anorexics) and "pro-mias" (bulimics) sometimes combine aspirational visuals -- ranging from shockingly skeletal close-ups of rib cages to full-length portraits of thin, beautiful celebrities such as model Kate Moss -- with tips on hiding self-starvation from parents and suggestions on the bare minimum you can eat to stay alive. In the twisted world of pro-ana and pro-mia motivation, misery loves company, and the secretive, isolated ED sufferer feels the pull of community.

"They try to normalize it," said Jillian Lampert, director of communications, outreach and research for the Emily Program in St. Paul, a nationally known ED treatment and prevention center. "They are fake friends encouraging sickness."

Even if viewers don't have a diagnosed eating disorder, the images can push someone on the cusp over the edge, she said: "Just gazing at the photos can impact their body satisfaction and their eating habits -- no matter that the majority of these pictures are altered."

According to estimates for Minnesota compiled by sources including the National Institute for Mental Health and studies published in psychiatric journals, about 8 percent of girls and 4 percent of boys ages 10 to 17 have an eating disorder. Among adults, the percentages are 6 percent for women and 3 percent for men.

Kezia Gayan of Minneapolis developed her ED, a combination of anorexia and bulimia, when she was a college freshman.

"I would eat small amounts, like two cookies, and then purge," she said.

Now 25, a former Emily Program patient in recovery and working on a master's degree in family therapy, Gayan sees thinspo followers as falling prey to "a dangerous sort of groupthink." While she says she didn't visit such sites often, "they can definitely be a trigger. They can help you feel like what you're doing isn't wrong."

Some posters include disclaimers calling their passion a "lifestyle choice." But the provocative photos speak louder than their words. Others, trying to evade tightening social-media restrictions, reposition themselves as "fitspo" enthusiasts, tying in images of bodies engaged in exercise and athleticism, "but many of the pictures are very much the same," Lampert said. "They don't seem to make the connection that athletes need enough fuel to perform well."

While ED experts compare thinspo to showing a junkie how to order heroin online, some bloggers and commenters have expressed uneasiness over social-media platforms being the arbiters of what is and is not OK to post.

Leita Walker, an attorney with Faegre Baker Daniels who often writes terms of use for social media sites, says such policies are not a First Amendment violation.

"The owner of the platform can decide what kind of content they're going to allow," she said. "The Apple store can say, 'We're not allowing pornographic apps in our store.' Facebook can say, 'We're not going to allow obscene content or pro-ana content.'"

People may be rightly concerned about the power of large social-media platforms to censor, she said, "but that has to be remedied through market pressure as opposed to a legal claim under the First Amendment."

Because eating disorders have the highest death rate of all mental illnesses, "to take this lightly, this encouragement of sickness, is ridiculous," Grefe said. "Would we not have a problem with a site that was pro-leukemia?"

Kristin Tillotson • 612-673-7046