LOS ANGELES (CBS) — It’s one of the most popular and fastest growing social networking sites online but some women are using Pinterest to feed their eating disorders.

Pinterest, a self-described “online pinboard”, is popular with women, who pin pictures of their favorite fashion and food items, wedding ideas and lifestyle concepts. The site is the third most popular social networking site, following Facebook and Twitter, according to Forbes magazine.

Nadine Bivens, who teaches Zumba at Body Rush in Studio City, said Pinterest helps her stay on track with fitness.

“It’s nice to have an image that you’re shooting for,” said Bivens, who pins photos of celebrities like Mel B to motivate her. “Every little thing looks fit, tight, defined, and I just think that’s an image of a great body!”

But there’s also a dark side to the site.

If you take it further, and search for “anorexic”, “thinspiration”, or “thinspo” on Pinterest, disturbing images come up of emaciated bodies and pro-anorexic slogans.

“When I could see my bones and stuff, I was like, “OK, I am thin! I have gotten there,” said Sara, a Westwood resident.

Sara is recovering from anorexia and didn’t want to show her face on camera, but said, in her darkest days, negative images like those found on Pinterest fueled her disorder.

“Now that I have gone through all of this, I look at those pictures and I can’t believe, like I watched “Black Swan”, and can’t believe I wanted to look like that,” Sara said.

Dr. Stacey Wadlington is a licensed clinical psychologist in Beverly Hills and said Pinterest needs to do more to monitor these images.

“To put these things out there, without the understanding of the impact on the youth, is a tad bit irresponsible,” Wadlington said.

Because of the controversy, Pinterest recently changed its policies about posting inappropriate content, stating: “We updated our acceptable-use policy and we will not allow pins that explicitly encourage self-harm or self-abuse.”

Pinterest recently partnered with the National Eating Disorders Association, so when someone searches terms like “thinspiration”, a link and numbers for help hotlines appear at the top of the site.

Pinterest also has a report option on every pin, so visitors can flag and report pins.

With millions of active users on the site, the site is a source of inspiration. And, as the site says, it’s a place to “organize and share things you love.”

Bivens said you go on Pinterest and, “You strive for something, you see something, and you’re like I want that for myself,” — as long as the goal is a healthy one.

If you or someone you know thinks they have an eating disorder they can find help here: http://www.nationaleatingdisorders.org/index.php