Last week, eighth graders at an Indiana school were asked to explain the body mass index (BMI). But one girl in the class had a little more to say than everyone else. In a letter that has now swept across the internet, she discusses why the measure is outdated, flawed, and used as a basis for way more health standards than it was ever intended to be. In her letter, the student explains that since she's a softball player, her body is muscular and bigger than some of her classmates'. But the BMI can only estimate your body fat or muscle percentage, because its calculation only accounts for your height and weight. So it sometimes labels athletes such as this student as "overweight" or "obese" — words that are (unnecessarily) loaded with stigma in today's culture. Although the BMI can be useful (it's so easy and cheap to do), it's too often used as a shortcut that doesn't offer a clear picture of an individual's health. A recent study published in the International Journal of Obesity, for example, looked at data from American adults who participated in the National Health and Nutrition Examination Survey and found that nearly half of those classified as "overweight" and a third of those classified as "obese" had perfectly healthy blood pressure, cholesterol, and insulin levels. Even the CDC recommends against using the BMI as a marker of overall health.
And this student nails it. As she writes, you are more than your BMI; what you eat, how active you are, and your other biomarkers (such as blood pressure) all help make up the larger picture of your health. After talking with her doctor, the student confirmed that she was perfectly healthy — despite her BMI. "I am just beginning to love my body, like I should," she writes. "My BMI is none of your concern because my body and BMI are perfect and beautiful just the way they are."