Their Worst Nightmare

To what we imagine is the dismay of health professionals, David Brooks delivers an almost perfect misreading of the latest report linking obesity, overweight, and early death.  Briefly, the study may be confounded by the difference between "fit" and "fat" - for example, buff guys can score as overweight.  However, contra Brooks, the study surely did not conclude that exercise was futile, or harmful.

John Luik of TCS provides some nuance while bashing the study.

Developing...

MORE:  Ogged pummels Brooks, so we don't have to.  However, we feel obliged to extract this as the silliest idea from Mr. Brooks' silly column:

...it seems that Mother Nature has built a little Laffer curve into the fabric of reality: health-conscious people can hit a point of negative returns, so the more fit they are, the quicker they kick the bucket. People who work out, eat responsibly and deserve to live are more likely to be culled by the Thin Reaper.

No, no, and no.  Here is a link to the full study; we extract this caveat:

We used the current federal definitions of overweight and obesity, which are based only on BMI, not on body composition. Our estimates give numbers of excess deaths associated with different levels of body weight, but the associations are not necessarily causal. Even if body weights were reduced to the reference level, risks might not return to the level of the reference category. Other factors associated with body weight, such as physical activity, body composition, visceral adiposity, physical fitness, or dietary intake, might be responsible for some or all of the apparent associations of weight with mortality. Additional investigation of the effects of body composition and visceral adiposity on mortality would be of interest.

So, contra Brooks, the authors did not attempt to sort out the possible health benefits of physical fitness (I blame this on data limitations, although that appears to have changed in 1999).  Here is what they tell us:

The final model included BMI categories, sex (male, female), smoking status (never, former, current), race (white, black, other), and alcohol consumption categories...

But no measures of physical fitness.  And, it is important to keep in mind that that the study focused on deaths.  The authors add this:

We did not examine other health problems caused by obesity. A recent population-based study has found that overweight and obesity have a strong and deleterious impact on important components of health status, including morbidity, disability, and quality of life, and this impact is disproportionately borne by younger adults.⁴⁰ Nor did we examine cause-specific mortality. Overweight and obesity may be more strongly associated with cardiovascular mortality than with total mortality.

Finally, folks who want an easy number to factor in to the BMI calculation can simply check their waist measurement - for men, a waist measurement above 40 inches is associated with increased risk; for women the key number is 35.

STILL MORE:  It's all here somewhere - the NIH Clinical Guidelines for Overweight and Obesity, the New England Journal of Medicine Guidelines for Healthy Weight, and this study telling us why the Body Mass Index is so widely accepted.

Fit versus Fat is discussed in a WebMD article featuring Campos and Cooper - Campos is the author of "The Obesity Myth", and Cooper is the Cooper Institute, founded by Dr. Ken Cooper.  And from the President's Council on Physical Fitness (2000) we see another Cooper-inspired article on the protective effects of fitness which flatly contradicts Brooks:

The studies reviewed above demonstrate a strong protective effect for physical activity and physical fitness on the health risks associated with   obesity. Consistent differences in health risks were evident between fit and unfit individuals among all body composition categories.

We contrast that with Brooks:  "People who work out, eat responsibly and deserve to live are more likely to be culled by the Thin Reaper."

AHHHH!

Comments

[TM]

Some data from Europe.

Here is a nutrition blog, and another.

http://www.timesonline.co.uk/article/0,,3-1563822,00.html

The IFIC is sponsored by the food industry, but they suggest places to look.

[JorgXMcKie]

Does that 40 inch thing count if I can suck it up to under 40?

;->=

[TM]

Just don't hold it in too long, or you'll keel over from a heart attack.

[David Walser]

I didn't take Brooks as saying exercise had no benefits. His point (to the extent a humorous column has one) seems to be that extremes are bad. It is possible to exercise too much and it is possible to be too heavy.

[Chris]

Another stupid thing about the Brooks piece is that he attributes a quote about "survival of the fittest" to Darwin, which is obviously wrong -- that phrase was coined by Herbert Spencer.

[TM]

From Brooks:

People who work out, eat responsibly and deserve to live are more likely to be culled by the Thin Reaper.

That is hardly a call for moderation in all things.

Look, if he had singled out ultra-marathoners, he would have had a point. Not a point supported by this study, but a point nonetheless.

But "work out and eat responsibly" is a pretty broad category.

[pdq332]

If Brooks was misreading the data in his column today, then how about the conventional wisdom that "thin is always better than fat" that evidently rested upon a previous misreading of the data? If Brooks is a little bit guilty of pooching the interpretation of a few technical terms like "fitness" and "BMI", it is worth it to strike a blow against the food police.

It is a serious issue, since as recently as last week the next big wave of lawsuits in the US was going to be against the food industry and was going to be about obesity, and the next factor in my insurance costs was going to be my BMI. But like David Brooks, I am having so much fun watching folks back away from BMI as a good measure now, all of a sudden, with their Ptolemaic attention to previously unheard of measures like morbidity and adiposity, and all of the like struggling to hold on to an old religious paradigm that rewarded excessive exercise and fasting.

Thin versus fat, sedentary versus active, the truth as usual lies somewhere in the middle.

[TM]

More on the public policy implacations in this paper by Kendall Powell.

[TM]

More reactions - the Times editors aren't too bad; Tierney wins the "As Confused As Brooks" prize for this:

After decades of listening to emaciated ascetics lecture us about diet and exercise, it's tempting to return the favor. We could turn into activists ourselves and stand in picket lines outside gyms with signs proclaiming, "StairMaster = Death."

[Half Sigma]

While you bring up valid points that BMI is not such a good way of measuring overweightness, it ignores muscle mass, frame, sex, race, etc.

BUT, the study is VERY CLEAR that the advice that the CDC has been giving us for years, that thin means healthy, was completely wrong.

As I explained in my blog, 20,000 deaths per year have been caused by bad government advice on weight.

Furtheremore, I'd say that there's no evidence that having more muscle means a longer life, people who exercise just want to think that.

[Half Sigma]

I would further point out that the average person in the data samples would be an average not especially athletic American of either sex... we are not talking about bodybuilders. For a regular person who's 50 years old and not any more athletic than the average 50 year old, this study would show that an "overweight" BMI of 27.5 is healthier than the BMI of 22.5 that we have been mislead into thinking is healthy.

[TM]

Furtheremore, I'd say that there's no evidence that having more muscle means a longer life.

If you have a specific point in mind - that body-builders, as distinct from cyclists, do not gain a health benefit from their fitness regime - I suspect that the evidence may not be clear. Apparently, the Cooper Institute has been a big source for the long term studies, and they have focused on aerobic fitness since the 60's (when I first heard about Dr. Ken Cooper, IIRC).

However, if you have a broader point in mind - if "muscle" is a metaphor for physical fitness, and your position is that physical fitness does not lead to better health outcomes - well, the link to the Coooper study hidden in the phrase "protective effects of fitness" strikes me as convincing.

As to "thin is not healthy", one of the studies I linked to had a doctor puzzling over that quite cogently. His gist - "the thin" tends to include the naturally thin, smokers, folks with a wasting disease (possiby undiagnosed), and folks with dubious lifestyle choices (alcoholics and the heroin chic).

Although the researcher's goal is to sort those groups and draw health conclusions about the naturally thin, one never knows. His guess is that the data is confounded by the unhealthy thin, not that being thin is unhealthy.

That said, chemotherapy treatment for cancer generally results in weight loss, so a possible benefit to carrying a few extra pounds would be "chemo insurance" - an overweight person newly diagnosed with cancer ends chemo on the skinny side; an underweight person ends chemo dead (weakened by hunger, susceptible to disease). Maybe.

[TM]

20,000 deaths per year have been caused by bad government advice on weight.

Maybe - if folks were actually taking the government's advice.

But how do we account for the huge numbers of huge people who ignore the advice?

And why blame the government? Hollywood, the media, and the publishing industry all promote "slim". And they are all ignored, too.

[Half Sigma]

My assumption was that one third of those in the "normal" category might be in the "overweight" category were it not for the bad government advice.

An assumption pulled out of thin air, but it demonstrates that false advice leads to more deaths than the war in Iraq.