The Obesity Myth

Matt_Simpson

Megan McArdles blogs an interview with Paul Campos, author of The Obesity Myth. I'll let anyone who is interest read the whole thing, but here's some interesting excerpts:

I mean, there's no better established empirical proposition in medical science that we don't know how to make people thinner. But apparently this proposition is too disturbing to consider, even though it's about as well established as that cigarettes cause lung cancer. So all these proposals about improving public health by making people thinner are completely crazy. They are as non-sensical as anything being proposed by public officials in our culture right now, which is saying something.

It's conceivable that through some massive policy interventions you might be able to reduce the population's average BMI from 27 to 25 or something like that. But what would be the point? There aren't any health differences to speak of for people between BMIs of about 20 and 35, so undertaking the public health equivalent of the Apollo program to reduce the populace's average BMI by a unit or two (and again I will emphasize that we don't actually know if we could do even that) is an incredible waste of public health resources

and

Megan: An economist recently pointed out that we don't encourage people to move to the country, even though rural people live more than three years longer than urban people, and the diffefence in their healthy life expectancy is even more outsized. Nor do we encourage people to find Jesus or get married. We target "unhealthy" behaviors that are already stigmatized.

Paul: Right, as Mary Douglas the anthropologist has pointed out, we focus on risks not on the basis of "rational" cost-benefit analysis, but because of the symbolic work focusing on those risks does -- most particularly signalling disapproval of certain groups and behaviors. In this culture fatness is a metaphor for poverty, lack of self-control, and other stuff that freaks out the new Puritans all across the ideological spectrum, which is why the war on fat is so ferocious -- it appeals very strongly to both the right and the left, for related if different reasons.

Megan McArdles blogs an interview with Paul Campos, author of The Obesity Myth. I'll let anyone who is interest read the whole thing, but here's some interesting excerpts:

I mean, there's no better established empirical proposition in medical science that we don't know how to make people thinner. But apparently this proposition is too disturbing to consider, even though it's about as well established as that cigarettes cause lung cancer. So all these proposals about improving public health by making people thinner are completely crazy. They are as non-sensical as anything being proposed by public officials in our culture right now, which is saying something.

It's conceivable that through some massive policy interventions you might be able to reduce the population's average BMI from 27 to 25 or something like that. But what would be the point? There aren't any health differences to speak of for people between BMIs of about 20 and 35, so undertaking the public health equivalent of the Apollo program to reduce the populace's average BMI by a unit or two (and again I will emphasize that we don't actually know if we could do even that) is an incredible waste of public health resources

and

Megan: An economist recently pointed out that we don't encourage people to move to the country, even though rural people live more than three years longer than urban people, and the diffefence in their healthy life expectancy is even more outsized. Nor do we encourage people to find Jesus or get married. We target "unhealthy" behaviors that are already stigmatized.

Paul: Right, as Mary Douglas the anthropologist has pointed out, we focus on risks not on the basis of "rational" cost-benefit analysis, but because of the symbolic work focusing on those risks does -- most particularly signalling disapproval of certain groups and behaviors. In this culture fatness is a metaphor for poverty, lack of self-control, and other stuff that freaks out the new Puritans all across the ideological spectrum, which is why the war on fat is so ferocious -- it appeals very strongly to both the right and the left, for related if different reasons.

Yes: diet and exercise. That's exactly how you make people thinner. The problem -- there are competing truths here -- is that diet and exercise isn't the easy solution it seems to be. How do you implement calorie restriction and exercise? This is what Paul is talking about when he says we don't know. (But I think his choice of words suggests that the "diet and exercise" message is debunked or something.)

Re: "There aren't any health differences to speak of for people between BMIs of about 20 and 35"

Uh, reality check!

There not any doubt that health is affected over this range (imagine here the BMI of a single individual varying over this range) but the problem -- to mediate again -- is that BMI is not a reliable measure of unhealthy fat, so you can't accurately compare the health of two different people by their BMIs, or really have a good gauge of your own health from your current BMI. Paul Campos is exploiting this confusion. It would be incorrect (and intellectually dishonest) to connect this message about BMI with the message that it's just as healthy to be 30 pounds overweight.

Some discussion of the connection between health risks and BMI here and the limitations of BMI as a measure here.

I haven't read the book, so I don't know if Paul Campos actually asserts that being fat is healthy, and unrelated to diet and exercise, or if he is deliberately misleading in order to whip up interest in his book.

Yet there's at least one true message: for people who have a healthy weight but a high BMI (for their height, thanks Psychohistorian), they can consider themselves healthy because they're not overweight.

healthy weight but a high BMI

This is a little vague. "Healthy weight" is contingent on height, so the term is, at least, imprecise in this context. I'm guessing your point is that BMI is contingent on build as well as height, which is absolutely true and which the article you linked kind of misses out on.

BMI assumes that people get thinner (or relatively slighter-framed) when they get taller which I believe is generally but not universally true, and it assumes people don't have a lot of muscle. There's enough variance in the population that th... (read more)

16

The Obesity Myth

16

16

16

The Obesity Myth

16

16