28 January 2015 - EurekAlert - Seeing selves as overweight may be self-fulfilling prophecy for some teens

The researchers used the National Longitudinal Study of Adolescent Health, known as Add Health, to examine height, weight, and self-perception data from a total of 6523 adolescents who participated in the study when they were about 16 years old and again when they were about 28.

At age 16, the participants were asked to rate how they thought of themselves in terms of weight, with response options ranging from very underweight (a score of 1) to very overweight (a score of 5). The researchers were specifically interested in looking at the outcomes for teens who saw themselves as overweight, even though they were a healthy weight by medical standards.

Compared to teens who perceived their weight accurately, adolescents who misperceived themselves as overweight had a 40% greater risk of becoming obese as adults, defined as having a body mass index of 30 or more. This misperception was also associated with the overall amount of weight the adolescents gained.

But why would seeing themselves as heavier than they actually are predispose teens to later weight gain?

There are probably several mechanisms at work, say Sutin and Terracciano. These teens may be more likely to engage in unhealthy weight-control behaviors, like using diet pills or vomiting, that are known to be associated with long-term weight gain. The psychological factors that lead them to misperceive their weight might also be linked with lower self-regulatory abilities. And the teens are likely also influenced by weight-related stigmatization, which is itself associated with obesity.