Jezebel posted today on a perennial favorite among feminist bloggers: the BMI. This was prompted by a doctor in the New York Times talking about how useless a measure it is for personal health.
Here’s my response: of course it is. It’s an index. This is what indexes do, they aggregate individual pieces of information to tell you something about a whole. The BMI was never intended to be used as a measure of personal health, but was instead meant to tell us something about entire populations. It’s usefulness on that score remains intact: you can broadly say that, if America’s BMI average is increasing, Americans are getting fatter. Unless it can be explained by something else, like a population-wide protein-shake/weight-training-routine frenzy, which is unlikely to happen.
But here’s what that doesn’t mean: that using your weight as one of the things that assesses your health isn’t useful at all. That’s what Dodai seems to be implying at Jezebel when she says this:
In our society, we’re so quick to call someone who appears to be fat “unhealthy.” But health is not a quality that can be judged or seen with the naked eye. There are thin people who smoke and don’t eat any vegetables. There are obese people — including Steven N. Blair, one of the nation’s leading experts on the health benefits of exercise — who jog every day. You can’t see genetic material, a decaying liver or gingivitis in a photograph.
Can you judge health with a naked eye? It’s true, you can’t. But let’s be honest, there’s not an epidemic of fat runners out there. Those people are outliers, and not everyone is an outlier. I’m with people who argue that we shouldn’t focus solely on weight in public health debates, and that we should be talking about eating better and exercising as a way to promote health without reinforcing, intentionally or not, the notion that some body types are better than others. But, by and large, (pardon the expression) weightier people suffer health problems that are well documented. It’s not that thin people are necessarily fit. It’s that America as a whole is unhealthy, and one of the ways we can document our decades-long decrease in activity is by documenting our expanding waistlines.
In all, this demonization of the BMI is odd. I’m outside my normal BMI range, but I’ve never had a doctor say, “Boy, are you overweight!” I have had doctors ask me what’s happening when I come in for my yearly check-up and my weight’s gone up or down. They’re never concerned when I’ve put on ten pounds; they’re concerned when I tell them it’s because I’ve stopped exercising. Likewise, no doctor talks about my weight when she does routine blood tests, listens to me breathe or feels my glands. I’ve only ever heard doctors talk about the BMI in public health contexts; when they talk about groups of patients or populations as a whole.
At the same time, I hope a doctor would tell me if I’ve put on too much weight and it should cause concern. That’s what doctors are for. Counseling you on the health risks of, whatever. Weight can signal a lack of activity or too many donuts, and that shouldn’t irk anyone. Yet, it does.
UPDATE: Comments to this post are closed, since just about everything possible to say has already been said. Thanks, everyone, for reading and commenting.