Earlier this week, the Journal of the American Medical Association came out with a huge study of obesity that concludes that the obesity hysterics are, indeed, hysterical. Their results indicate that being moderately overweight or even very mildly obese doesn’t make you more likely to die than a thin person. In fact, it may make you less likely to die, to the tune of 6%. (Severe obesity, however, did show a strong connection to higher death rates).
Now you would think that this would be greeted with some skeptical enthusiasm. If the results are born out by further study, it would mean we do not have a massive pending public health crisis on our hands. It means that instead of using cattle prods to get moderately overweight people into the gym, we can concentrate on really obese people.
So is the health community greeting this with relief? Not exactly:
That’s the wrong conclusion, according to epidemiologists. They insist that, in general, excess weight is dangerous. But then they have to explain why the mortality-to-weight correlation runs the wrong way. The result is a messy, collective scramble for excuses and explanations that can make the new data fit the old ideas.
William Saletan at Slate lists a dozen different explanations for why this study is wrong, definitely wrong, absolutely wrong, no sir. Most of these cross him (and me) as trying to rationalize away an inconvenient scientific result.
To go through them:
Here’s the thing: the entire discipline of public health would be much more useful if we simply dumped the Fucking Useless BMI (hereafter FUBMI). Why on Earth we decided to use a bit of 19th century pseudoscience as our end-all, be-all for measuring health mystifies me.
We all have heard about the muscle thing. Muscular people have higher FUBMI’s and better health. In grad school, I worked out for a while and my BMI went up because I added muscle. But I felt great.
But the muscle thing isn’t the only reason to discount FUBMI. It’s that some people simply have bigger bodies and bigger frames. I have big shoulders and muscular legs, as do many men. There are lots of women who have big hips, no matter how much they starve themselves. None of us is ever going to be in the ideal weight range unless we get down to death camp survivor levels. Does that make sense?
The FUBMI thing reached its awful nadir in public schools, where children were sometimes weighed and shamed in front of their classmates. Childhood obesity is something to be worried about, no question. But using the FUBMI in those circumstances is insane. Any parent knows that children can cycle quite a bit, packing on some weight right before a growth spurt. In just five years, I’ve watched my daughter’s belly get big for a while and then shrink again when the growth spurt hit. I saw her FUBMI go up and down on the doctor’s charts because she was quite a bit head of the growth curves. Fortunately, our pediatrician we smart enough to ignore the FUBMI and concentrate on the healthy active girl in front of him. Many pediatricians and teachers are not that smart and start talking about diets and portion control for toddlers.
The FUBMI is a piece of shit. It has distorted and ruined any scientific discussion of obesity. In the article they talk about slightly better things like waist-to-hip ratios and body-fat percentages. But those are just fancier FUBMI’s. Blood pressure, blood lipids, glucose, cardio-respiratory fitness — that’s useful. But also more difficult and more expensive to measure.
(Part of me wonders if there’s a wisdom of crowds thing going on here. Obesity has leveled off in the last few years despite predictions that it would continue to rocket upward. I’m wondering if we’re finding a level that is the right intersection of health, happiness and a life not spent crying over the scale. Obviously, there’s a distribution: some people at “ideal” weight, some people obese. But I would not be terribly surprised — a little surprised, but not terribly — if research shows that we’re leveling off at level that acceptably trades health risk for happiness.)
Frankly, I think what this study means is that it’s back to the drawing board on obesity. I don’t think this study shows that obesity isn’t bad for you (and it doesn’t) or that being overweight isn’t necessarily bad. I think it shows that our obsession with weight and in particular the FUBMI has been wrong-headed. Fitness, diet, lifestyle: these are far more important.
We need to refocus on the inputs. Encourage people to eat better and get exercise and get off the couch not because it will make them lose weight and look like Heidi Klum or something but because those things are good things in and of themselves. If you lose weight and look good, well, that’s low-calorie gravy. But the inputs are what matters, not the outputs.
An overweight person who gets regular exercise is in better health than a skinny person who doesn’t. Most people who exercise do not lose a lot of weight unless they are obese because their bodies, told by millions of years of evolution that losing weight is a bad thing, will make them eat more to compensate. They then get discouraged and quit. This travesty results from a wrong-headed approach to public health and our obsession with weight the the FUBMI.
Encourage healthy lifestyles. Let evolution and the wisdom of crowds handle the rest.
(And when I say “encourage people” I don’t mean government. I mean society at large: doctors, public health advocates, nurses. You know, people who actually do stuff.)