By Amanda Salazar

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Across the country, schools require students to participate in fitness tests. Children are expected to run laps at pace with an audio track, to count how many consecutive sit-ups they can perform, and to step on a scale for weight measurements. A few weeks later, they receive a pamphlet with their results. 

 

Prominent in this pamphlet is the student’s Body Mass Index — a tool used to categorize weight that is often unreliable as it doesn’t consider muscle index and other weight factors. This practice has been implemented for several years, thinking that notifying the students of their BMI, particularly if it’s considered “overweight,” would inspire them to eat healthy, work out, and lose weight.

 

In reality, it’s possible that practices to inform adolescents of their weight category, including school fitness and BMI tests, can cause more harm than good.

 

A study published in The Journal of Adolescent Health recently found that informing teenagers of their weight category is associated with the development of disordered eating habits, such as skipping meals, abusing laxatives, binge eating, and self-induced vomiting. These habits, the researchers found, often persist well beyond the school years and into adulthood. 

 

“I think it means that we need to think critically about any of our public health policies and our clinical recommendations that are inherently based on notifying individuals of their weight status, to think about the potential harms of doing so,” said study author Dr. Samantha Hahn of the Central Michigan University College of Medicine.

 

The researchers used data from Project Eat, a research project from the University of Minnesota School of Public Health. Project Eat followed more than a thousand teenagers from Minneapolis-Saint Paul, Minnesota, and surveyed them on how they categorized their weight and eating habits. 

 

Middle and high school students responded to surveys at four points in their lives, starting at about 13-16, which the researchers considered early adolescence. Questions at this age included gender, race, socioeconomic status, and whether they believed themselves underweight, the right weight, or overweight. The surveys didn’t focus on actual weight, only on how the students perceived their weight. Students replied to surveys again in late adolescence, or 17-21. This time, the survey also asked whether they ever engaged in what the researchers consider “disordered weight control behaviors” — fasting, purging, and more — or in binge eating.

 

The final two surveys posed the same questions, but dropped the weight perception question since the focus was meant to be on the behaviors caused by the perceptions. These surveys were done at emerging adulthood, 23-27, and young adulthood, 28-33.

 

Hahn’s team found that participants who considered themselves overweight at both points in adolescence were the most likely to develop disordered eating habits, followed very closely by participants who began considering themselves overweight during late adolescence. Those who never considered themselves overweight made up the smallest percentage of participants who partook in disordered eating. 

 

Teens who thought they were overweight were not only more likely to engage in disordered eating behaviors as a teenager but also for years into adulthood, implying that the way people think about themselves can have long-lasting effects.

 

“There are clearly long-term implications of perceiving ‘overweight,’” Hahn said.

 

This study builds on what has already been determined about the strong association between self-perception and disordered eating by looking at the impacts of the change in self-perception throughout adolescence. 

 

Considering yourself overweight at 13 to feeling overweight at 18 results in nearly as much disordered eating as identifying yourself overweight the entire time. 

 

“I think that this study just adds to the idea that having a positive perception about oneself is helpful, and it’s when that perception becomes less positive that you see the bad outcomes,” said Northeastern University psychology professor Dr. Rachel Rodgers.

 

All of these findings were based on “weight perception” — meaning, they were based solely on how the participants viewed themselves, regardless of their actual weight. In fact, overweight-identifying participants were less accurate with their perceptions than those who didn’t consider themselves overweight.

 

Additionally, the study found that once a person starts thinking of themselves as overweight, it’s likely this thought process will persist for the rest of their life.

 

The conclusions suggest that practices and policies centered around telling adolescents whether they’re overweight or not could be associated with increased disordered eating habits. In essence: telling a teenager that their BMI falls into the “overweight” category might lead them to develop disordered eating habits, not to eat healthy and lose weight.

 

“Were any of this to be helpful, it would be important to do it in a really supportive way that doesn’t overemphasize, for young people, the importance of weight generally, or shame them in some way,” Rodgers said. “Contrary to popular belief, shame does not drive positive behaviors.”