A disturbing fad is becoming commonplace in the world of social media. Young women are turning to the personal blogging site Tumblr and other social networking sites for information on and photos of the “thigh gap,” a possibly dangerous weight-loss goal that experts say could motivate disordered eating and excessive exercise.

A thigh gap refers to the space between a person’s thighs when their feet are together, a body trait found in some fashion models, but rarely found in the general population. Young women are turning to social networking sites to photo blog their quest to obtain a thigh gap (#thighgap) or share information on how to get one. Methods range from exercises targeting the inner thigh to diets bordering on starvation.

“The issue of focusing on a particular body part is very common,” Claire Mysco of the National Eating Disorders Association, told USA Today. “What is new is these things have taken on a life of their own because of the Internet and social media.”

The relationship between social media and disordered eating was studied in 2011 at the University of Haifa. Researchers found that adolescent girls who spent the most time on Facebook were at the highest risk of negative body image. Whether negative body image is fueled by surfing other people’s photos or vice versa, remains a mystery.

“The ability to be instantly connected to everybody and see what they look like and see them blog or talk about what they are eating and what they do for exercise — this makes it a lot more difficult for those with eating disorders,” said Kim Callaway, a therapist who works with people with eating disorders, in an interview with USA Today. She encourages her clients to delete their social media pages.

What makes the thigh gap trend more dangerous is that, for many, getting one is neither healthy nor possible. Even very thin people may not have a thigh gap, which requires hips to be wide as well, a trait based on genetics, according to orthopedic surgeon Dr. Vonda Wright.

“Skinny does not mean fit or muscular,” said Wright in an interview. She also noted that athletes tend to lack a thigh gap because of muscle.

Just as it's difficult to blame social media for the proliferation of eating disorders such as anorexia and bulimia, it's impossible to say whether the thigh gap trend is the cause or the result of disordered eating for any individual. As anorexia and bulemia are disorders characterized by obsessive and compulsive thinking about body image, the thigh gap could simply serve as a tangible focus for an underlying disorder.

Sara, a person who struggled with anorexia and wishes to remain anonymous, said that she was a frequent visitor of thigh gap websites.

"It helped to normalize what I was doing to myself," she said. "I never knew before that I wanted a thigh gap. It felt like it was some type of accomplishment that people would want to achieve."

Some social media users hope that sites could be used to generate more positive thinking over non-emaciated body types. A counterblog titled "f*** yeah! touching thighs!" was created on Tumblr.