For the love of all that is holy, can someone please put the final nail in the coffin of BMI? This bogus “health measurement” has been disproved time and again, yet, like body weight alone, lives on in its discriminatory assessments, despite offering no direct bearing on a person’s individual health.
Let me say that again: Weight and BMI are fundamentally unhelpful measurements on an individual basis when determining a person’s health.
To fully understand what I’m saying, you need to wrap your head around three factors: What, exactly, weight is; what BMI is; and ultimately, what health is.
Health, in and of itself, is simply the absence of illness or injury. If you don’t have an illness or injury (including chronic predictors of illness, such as high blood pressure, high cholesterol, or yes, even high levels of fat that qualify you as obese), then you are, technically, healthy. Does this mean you’ll always be healthy? Does this mean you’re not at risk for future illness or injury? Of course not. But, if you go to the doctor today and you’re given a clean bill of health, you are, by definition, healthy.
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Weight, by definition, is simply the way in which the mass of an object (or in this case, a person) is attracted to the earth by force of gravity. It’s how gravity pulls on your body. Nothing more, nothing less. It doesn’t say anything about how much fat or muscle you have. It doesn’t provide information about your blood pressure or cholesterol. It doesn’t assess how active you are during your day. It says nothing about your personal health or fitness.
Enter: BMI, or body mass index. For whatever reason, doctors started using this measurement as a “better” predictor of health sometime in the mid-’90s. The reasoning is that while body weight fails to take a person’s height into account, BMI does. And surely, then, if height is taken into account, shouldn’t BMI be a semi-accurate way to predict body composition, or a person’s leanness or fatness?
And yet, it’s completely bogus.
BMI does not, and cannot, accurately assess your body composition. It does not, and cannot, accurately assess whether a person is obese. And most importantly, BMI is fundamentally bad at predicting internal health on an individual basis.
In fact, an April 2016 study from the Intermountain Medical Center Heart Institute in Salt Lake City and Johns Hopkins Hospital in Baltimore found, yet again, that when compared with other measurements, BMI is fundamentally sucky at predicting risk of disease.
In this particular study, researchers looked at diabetic men and women without any apparent symptoms of coronary heart disease, then used total body weight, BMI and waist circumference to see which factor was most closely associated with regional left ventricular dysfunction, a common cause of heart disease.
The researchers concluded that a high waist circumference, often described as an “apple-shaped body,” is a much more accurate predictor of this particular heart dysfunction than BMI or total body weight.
Please put another nail in the BMI coffin.
All BMI is is a ratio of your height to weight. Like weight, it can’t say anything about your internal health. In fact, the Centers for Disease Control and Prevention recently updated their website to say, “BMI can be used as a screening tool but is not diagnostic of the body fatness or health of an individual. To determine if a high BMI is a health risk, a health care provider would need to perform further assessments.”
Boom. Thank you, CDC.
And yet, the measurement lives on. Partly because it’s so easy to assess, and partly because, in a broad, epidemiological way, it’s a helpful tool for predicting disease and risk across a broader community. But individually? It’s terrible and needs to be put out of our collective misery.
Can I get an amen?