When some teenagers gaze into a mirror, they see themselves as overweight, even though they’re not. This negative thinking becomes a self-fulfilling prophecy: Researchers found that teens that feel fat, but aren’t, tend to become fat adults (as if the teens years needed more awful baggage).
Koenraad Cuypers—a research fellow at the department of public health and general practice at the Norwegian University of Science and Technology— had observed an increasing amount of teens with flawed ideas about their weight, especially when faced with images in the media of waif-like models and actresses. He wondered if believing you were overweight could have an impact on your actual weight.
To understand how self-perception contributes to obesity, Cuypers looked at data from the Young-Hunt study (Nord-Trøndelag Health Study), a longitudinal study of teens and young adults in Norway. He first examined information from 1995 to 1997, which included 1,196 normal weight teens, and then looked at results from 2006-2008, when the subjects were between 24 and 30. The teens — 649 girls and 547 boys — viewed themselves as too fat, chubby, about the same as others, thin, or very thin.
Cuypers discovered that 22 percent of the girls thought they were too fat or chubby as teens. Of this group, 59 percent became chubby adults, if the researchers used BMI to measure obesity; if they used waist circumference, 78 percent were overweight. About 31 percent of the teens who thought they were normal weight became overweight adults according to BMI results, with 35 percent being fat according to waist measurements. When it came to the boys, 9 percent believed they were fat teens — again, even though they weren’t — and of this group, 63 percent became overweight adults.
“We did not expect that having a bad body image would affect weight gain so clearly,” says Cuypers.
Psychologist Frank Farley, who was not associated with the study, thinks the findings provide interesting information about how self-knowledge impacts people.
“[The study is] provocative to say the least,” says Farley, a professor at Temple University. “It also points to how important self-understanding and the self- knowledge are.”
Previous research in overweight people found that worrying about weight caused stress, contributing to weight gain. The teens that thought they were fat when they weren’t probably experienced the same strain, leading to bad behaviors. Fretting about waistlines encourages people to yo-yo diet and skip meals, both of which contribute to obesity. Or in some cases feeling fat can be self-defeating—these teens might overeat or exercise less because they feel chubby already.
Farley notes that the study did not prove causality, meaning the research doesn’t show that feeling fat causes people to become chubby. Also, he notes the results cannot automatically be generalized to the United States because of the differences between countries.
Despite not having a clear cause and effect relationship, the results show the powerful role the mind plays in obesity.
“Adolescence is an important period of life in regard to psychological and physical development,” says Cuypers. “Also, in this period, the basis for health behavior is laid which will affect lifestyle and health in adulthood.”
While Cuypers believes that these results could be use for public health campaigns that show healthy bodies and reinforce good behaviors, Farley urges concerned parents to consider therapy for children with self-perception problems.
“If your child is a teen or a tween and believes that [she is] overweight but objectively [is] not, work with [her],” Farley says. “Bring the perception into alignment with reality.”