Fitness Assessments Do Not Impact Teen BMI

In his book The Greatness Guide (HarperBusiness 2006), Robin Sharma wrote, “What gets measured gets improved.” Researchers from a new study might disagree. They found that regularly
measuring body mass index and categorizing teens as overweight (when they were) had minimal effect on future weight improvements.

Published in Proceedings of the National Academy of Sciences (2016;doi: 10.1073/pnas.1518443113), the study looked at more than 3.5 million BMI reports—gathered over 6 years—for New York City–area students. Parents were provided the results via annual fitness “report cards.” When analyzing the data, researchers focused particularly on girls whose weight fell near the overweight cutoff point. Some girls came in just above that point and were classified as overweight, while others came in a little below it and barely fell into the “healthy weight” range.

Unfortunately, the researchers found very little weight change among the girls who received the overweight classification.

“Whereas presumably an intent of BMI report cards was to slow BMI growth among heavier students, BMIs and weights did not decline relative to healthy peers when assessed the following academic year,” the authors stated.

They added, “Our results speak to the discrete categorization as overweight for girls with BMIs near the overweight cutoff, not to the overall effect of BMI reporting in New York City.”