Would You Want To Know Your Child’s BMI?

What Women Really Think
March 4 2013 3:00 PM

“Fat Letters” Are Not Outrageous Invasions of Students’ Privacy

BMI doesn't take muscle mass into account when designating kids "overweight" or "obese"

Photo by STR/AFP/GettyImages

Childhood obesity is one of the trickiest issues you can name. We want to protect kids from both Scylla (the adverse health effects of being overweight) and Charybdis (fat shaming). Given the delicacy of this subject, it’s odd but not totally surprising to watch the ire rain down on public schools in North Andover, Mass., for conducting BMI screenings on students and then mailing the confidential results home.

Katy Waldman Katy Waldman

Katy Waldman is a Slate staff writer. 

The screenings are part of a 2009 initiative from the Massachusetts Department of Public Health. After tests showed that 32.3 percent of students in the state were either overweight or obese, schools were required to collect the heights and weights of kids in the first, fourth, seventh and 10th grades, calculate their body mass indices, and convey what they found in a letter to the children’s parents or guardians. Parents of kids with BMIs below the fifth percentile or above the 85th percentile were further encouraged to consult a pediatrician. If they wished, parents could opt their kids out of the screening.


The so-called “fat letters” touched a nerve. In January, state Rep. Jim Lyons introduced a bill that would prevent schools from gathering BMI data from students. After a segment on WHDH TV, Jezebel chimed in with the critique that “singling out fat kids is not only unfair, it’s unproductive” (which is perplexing since all participating families receive their kids’ results). The Huffington Post conjured up a moment in the anti-childhood obesity wars we’d all like to forget—the infamous, fat-shaming ads from a 2011 campaign in Georgia.

Deep breath, everyone. Sure, “fat letters” sound horrible, but is the idea that schools might collect and transmit information about kids’ physical health really so outrageous? If we’re OK with schools telling us when our kids have poor eyesight or bad hearing (or lice!), why should weight remain so fraught? A piece of paper with a number on it has no native power: If parents and teachers work together to treat body size as just another health measure, BMI scores won’t be inherently stigmatizing. I would want my hypothetical children to attend a school that takes a holistic approach to their well-being—and that includes notifying me (even spurring me to action) if they’re too big or too skinny.

That said, the letters have to be done right. Ideally they’d be rolled into a more comprehensive report—just another piece of information—and upfront about the limitations of the BMI as a measure of health. (The index doesn’t differentiate between weight packed on by muscle and weight added by fat, for instance, which can lead to paradoxical classifications of fit athletes as obese.) And obviously, they should go straight to the parents, rather than being entrusted to the hands of babes, opened on the bus ride home, and used to fuel merciless teasing. (In fact, the missives are mailed directly to households, but recent press coverage has been misleading on this point.)

Of course, the most convincing arguments against the screenings don’t accuse North Andover schools of trespassing on students’ privacy, or of being tonedeaf to the angst of adolescence. They are the ones that tap into the question of whether obesity itself constitutes a health concern. To what extent is a BMI lower than 18.5 or higher than 25 actually dangerous? Is excess body weight a smokescreen—just a visible proxy for real problems like high blood pressure and heart disease? Furthermore, is it reasonable to assume parents in North Andover don’t already have a good idea of their child’s BMI score? And does the unwritten rule hold for kids as well as adults—that various ways exist to shrink your waistline, but having your size harped on isn’t one of them?

These are all legitimate questions. It’s possible, too, to imagine the Platonic ideal of the “fat letter,” which emphasizes diet and exercise rather than a kid’s physical properties, which is affirming and sensitive and full of life wisdom about how your character matters infinitely more than whether or not your thighs touch. But even if the communications could be improved, I’m not sure I see how their current incarnation—confidential notes with neutral numbers on them—does such grievous harm. 



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