The more teenage girls use Facebook, the greater their chances of developing eating disorders such as anorexia or bulimia.
Researchers at the University of Haifa interviewed 248 girls aged 12 to 19 on their internet and TV use, and gave them questionnaires on their views on slimming, their general outlook on eating and their sense of personal empowerment.
Perhaps predictably, there was a direct link between eating disorders and time spent looking at fashion sites. Surprisingly, though, Facebook was worse, associated with a far wider range of problems.
The results showed that the more time girls spend on Facebook, the likelier they are to suffer from eating disorders. They're also more likely to feel physical dissatisfaction and have a negative physical self-image and a negative approach to eating.
The team also found a direct link between eating disorders and watching gossip- and leisure-related television programs - Gossip Girl, and the like.
But the good news is that it seems parents can do a lot to help. Girls whose parents got involved in their internet use and talked to them about it were much less likely to have problems, with a stronger sense of self-empowerment.
"Significant potential for future research and application of eating disorder prevention lies in an understanding of how parenting decisions can have effect on an adolescent girl’s sense of empowerment and that enforcing a girl’s sense of empowerment is a means to strengthening body image," say the researchers.
"This study has shown that a parent has potential ability to prevent dangerous behavioral disorders and negative eating behavior in particular."