Monday, April 28, 2008

More scare tactics?

This story from the AP adds yet another entry to the annals of fat and thin. It covers new research that claims to show that fat-but-fit is a figment of the fatties' imagination.

The new study followed some 39,000 women with an average age of 54 over a period of 11 years, tracking their weight, levels of physical activity, and incidence of heart disease. Says the article:

Compared with normal-weight active women, the risk for developing heart disease was 54 percent higher in overweight active women and 87 percent higher in obese active women. By contrast, it was 88 percent higher in overweight inactive women; and 2½ times greater in obese inactive women.

Makes you want to start that diet now, right? But it's important to note that the women in the study were self-reporting their levels of physical activity, and self-reporters tend to overestimate when it comes to things like how much exercise they get. Steven Blair of the University of South Carolina points out that fat people who passed a treadmill fitness test did not face higher mortality from heart disease, a fact that seems to support the self-reporters' loophole.

Despite this study's sensationalized headlines, we still have no idea what is and isn't true when it comes to fatness, fitness, and mortality. But we do know that on the whole, diets don't work; that being physically active is better for your health than being sedentary; and that, as Ellyn Satter has shown time and time again, it's much better to be a competent and joyful eater than to be obsessed, anxious, and fearful around food.

So don't despair when you come across this study and the many news reports about it. Read it in context, understand what it does and doesn't say, and dance as much as you want.

7 comments:

sleepless said...

Good analysis. Also, we need to seriously consider what the incidence of heart disease was in this group. A 54% increase from, what was it, 1 or 2%, is still pretty *$%#ing small. I'm giving them the benefit of the doubt that this increase is actually statistically significant, too.

Actual numbers, peoples, actual numbers.

Rachel said...

I saw this study, too, and immediately thought "Wait, what methadology did they use to collect the date? and then saw the comments by Blair which confirmed my suspicions. With all the stereotypes against fat people already, what are the chances a fat woman would admit to a (presumably thin) doctor or researcher that all she did was sit on the couch and watch Lost? Nope, I ran two miles and scaled a mountain, would be my answer.

Studies like this are so disheartening. If all it took were scare tactics to get people thin, we'd all be thin. But losing weight isn't a simple matter of choice, even if you want it really badly and even when you are scared it threatens your life. So, this study basically says: "Attention fat people, no use in exercising because your fatness still poses significally higher health risks even if you are really active and fit."

Instead of trying to disprove why fat cannot be fit, why not try to show how fat can be fit and the health benefits it brings for all people, regardless of body weight, to be active?

galnoir said...

Even by this (flawed) study's own findings, being overweight and fit is better than being overweight and sedentary. But that point gets buried in the story.

And overweight/active and overweight/sedentary subjects are compared to "normal weight" people as a whole, without consideration for whether the "normal weight" subjects are active or sedentary.

I'm not 100% sold on the idea that being overweight is not unhealthy, but I really like the HAES approach because of its emphasis on healthy habits, which we all need. I'm afraid that the emphasis on "Fat is ZOMG! EVIL!!!!!" prompts people to crash diet, take pills, or seek gastric-bypass surgery in order to lose weight as quickly as possible. Stories like this just contribute to the panic.

Anonymous said...

They also left out one statistic I was interested in...

How did the "normal" weight, but sedentary women fare?

IrishUp said...

And for a slightly different perspective on what might actually be going on, is this intriguing review:
http://www.biomedcentral.com/1471-2458/8/128

The body politic: the relationship between stigma and obesity-associated disease
Peter Muennig

Abstract (provisional)

Methods
In this study, I reanalyze or review the relevant medical literature linking negative body image and health via stress pathways. I pursue novel lines of evidence to explore these linkages, and entertain alternative hypotheses that might explain the observed relationships.

Results
I forward four lines of evidence supporting the hypothesis that psychological stress plays a role in the adiposity-health association. First, body mass index (BMI) is a strong predictor of serological markers of stress. Second, obesity and stress are linked to the same diseases. Third, body norms appear to be strong determinants of morbidity and mortality among obese persons; obese whites and women--the two groups most affected by weight-related stigma in surveys--disproportionately suffer from excess mortality. Finally, statistical models suggest that the psychological desire to lose weight is an important driver of weight-related morbidity when BMI is held constant.

Conclusion
Obese persons experience a high degree of stress, and this stress plausibly explains a portion of the BMI-health association. Thus, the obesity epidemic may, in part, be driven by social constructs surrounding body image norms.

spinsterwitch said...

I posted this over at Rachel's, but it's good to point out here. There is a huge flaw in this study, and that is that the self report of weight, height and activity level were at baseline (the beginning) of an 11 year study. No interval measures of these factors were taken (even self-report). That's 11 years in which we do not have any data about what happened with these women in terms of exercise. It's just nonsense.

carrie said...

Spinster-

I didn't know that gap. I'm glad you pointed it out. I have a degree in epidemiology, and I find it so ironic how much store epidemiologists place in these studies. Every chronic disease epi course I've taken (2 full courses, and lots of bits and pieces) says that these kind of self-reports are notoriously unreliable. That a professional who supposedly knows this gets all hot and bothered about data that is hard to verify is absurd!