2 of 13

Poor body image

Negative or obsessive thoughts about body size, a key factor in all eating disorders, can occur very early on in the disease, says Cynthia Bulik, PhD, an eating disorders specialist at the University of North Carolina–Chapel Hill.

Warning signs of poor body image include negative self-talk ("I'm so fat," "I have no self-control") and misinterpreting other people's remarks. "Comments like, 'My, you have filled out nicely' can be received as 'You look fat,'" Bulik says. This body insecurity, she adds, sometimes emerges—or gets worse—when young girls compare themselves to idealized figures such as Disney princesses and rail-thin actresses.

Next: Excessive exercise