If you think you're fat, can it become a self-fulfilling prophecy? Yes, according to a new study in the Journal of Obesity.

Researchers in Norway used data from nearly 1,200 teenagers, both male and female, gathered from 1995 to 1997. All were normal weight at the time, but were asked if they considered themselves very fat, chubby, about the same as others, thin or very thin.

The same group was contacted about 11 years later when they were 24 to 30 years of age. Half of the participants still had normal weights. But among those who were overweight, the researchers found significant differences.

Fifty-nine percent of the girls who had felt fat as a teenager became overweight in adulthood, as measured by body mass index. When waist circumference was used as the measure instead, 78% of teens who had initially perceived themselves as heavy became overweight.

In contrast, 31% of the girls who did not consider themselves fat during adolescence were found to be overweight in the follow-up, as measured using BMI. That number was 55% when waist circumference was used.

Normal weight girls were more likely than boys to rate themselves as overweight. Twenty-two percent of girls and nine percent of boys saw themselves as fat or chubby in the first survey.

Researchers hope this study shines a light on keeping a level head on a healthy body image while taking into account natural differences in body type.