Newswise — CHAPEL HILL, N.C. -- College women who are more emotionally invested in Facebook and have lots of Facebook friends are less concerned with body size and shape and less likely to engage in risky dieting behaviors. But that’s only if they aren’t using Facebook to compare their bodies to their friends’ bodies, according to the authors of a surprising new study at the University of North Carolina School of Medicine.

In the study, 128 college-aged women completed an online survey with questions designed to measure their disordered eating. The researchers asked each woman whether she worried about her weight and shape and whether she engaged in risky behaviors such as using diet pills, vomiting after meals, or going on fasts. They also asked questions about each woman’s emotional connection to Facebook — her incorporation of the site into their daily life, time spent on the site each day, number of Facebook friends — and whether she compared her body to her friends’ bodies in online pictures.

“We really wanted to examine how each college woman used Facebook when posting pictures online. Is she thinking, ‘I’m posting this picture to share a fun moment with my friends’ or is she thinking ‘I want to post this picture to compare how my body looks to my friends’ bodies,’” says Stephanie Zerwas, PhD, Assistant Professor of Psychiatry in the University of North Carolina School of Medicine and senior author of the study published in the August 2015 issue of the Journal of Adolescent Health.

Because the perceived increase in women struggling with a negative body image is often blamed on the time they spend on social media, the researchers expected to find that greater Facebook intensity and online physical appearance comparison would be associated with greater disordered eating in college-aged women. They did find support for that assumption. When college women had a greater emotional connection to Facebook, they were more likely to compare their bodies to their friends’ bodies and engage in more risky dieting behaviors. However, what the research team found next surprised them most. As long as women weren’t using Facebook to compare their body size and shape to their Facebook friends, being more emotionally invested in Facebook was associated with less concern about body size and shape and fewer risky dieting behaviors.

“I think that Facebook could be an amazing tool to nurture social support and connections with friends and families. And if you’re getting that kind of social support from the site, you might be less likely to be worried about your body size. But if you’re using it as a measuring stick to measure how your body appears in pictures compared to your friend’s body, Facebook could also be used a tool to foster dangerous dieting behavior,” said Dr. Zerwas.

Morgan Walker, BS, was first author of the study and a college student while the study was underway. “While conducting this study, I couldn’t help but identify with the women in the study. It led me to examine my own social media habits," Walker said. "How do I spend my time on Facebook, and is it healthy for me? Having this research in the forefront of my mind made it easier to redirect my focus if I found myself falling into the trap of online physical or social comparisons. It’s also important to remember that one’s social media image is only an edited snapshot of their life, one that is likely not as perfect as it appears online.”

In addition to Zerwas and Walker, authors of the study include Laura Thornton, PhD, Cynthia M. Bulik, PhD, and Cheri Levinson, MA. All are members of the UNC Center of Excellence for Eating Disorders in the Department of Psychiatry. Munmun De Choudhury, PhD of Georgia Tech and Jaime Teevan, PhD, of Microsoft Research, also joined the research team.