Why That Fat Contagion Study Is Bunk

If you haven’t noticed this about my blog already, I tend to spend a lot of time debunking “bad science” studies. Sometimes the flaws are easy to spot. However sometimes they’re not.

And that’s when I jump to the internets to find some better analysis.

Remember that Fat Contagion study? The one that prompted my favorite abortion supporter to point out that maybe thinnies should stay away from fatties and everyone else in the media was way too polite to say this.

I had a gut feeling the science wasn’t all that but the problem was that I didn’t have the background to write about it.

But a post on Mondolithic reminded me that I had meant to post up this critique of the study by someone with an actual degree and the right background to take a look at the science of the study (and not just the conclusions).

Sandy Szwarc’s awesome blog Junk Food Science really had the goods on why Dr. Nicholas Christakis obesity study is not sound.

The issue isn’t that the study is built on using a statistical model. What I liked about Szwarc’s post is that she (who knows statistical model) knows that his model isn’t sound.

In other words, any pretense that these statistical machinations in any way resemble reality is a myth.

What did they find? None of the odds ratios their computer model came up with were tenable. But they didn't simply admit the null findings. Instead, they reported that obesity was associated less with genetic, familial ties; less with geographical proximity, as in immediate neighbors or even friends hanging out together socially; less with even being married and living, eating and sleeping together; than in simply being friends with a fat person. [But among the fine print: the weight gain of a fat friend wasn’t “contagious” if the friends were the opposite sex or among two females; the finding was only statistically significant among men.]

Which is something even if you accepted the model as sound is good to point out. Even in their own finding the result only showed results amongst male friends. I guess this means all my female friends (and male friends) are safe from me.

Really though I liked how she shed some light on the study’s author.

Whenever we come across a study with questionable science, that receives massive marketing and media attention far beyond its merit, and is being used to support sweeping public policy change, it’s time to ask why. But, in this case, Dr. Christakis declared “no potential conflicts of interest relevant to this paper.”

It may be of interest to learn, however, that he is on the Executive Committee of the Robert Wood Johnson Scholars in Health Policy program at Harvard and was elected to the Institute of Medicine last year. The Scholars website says it is “the most sought-after interdisciplinary post-doctoral fellowship program in the social sciences. Its purpose is to foster the development of a new generation of creative thinkers in health policy research.” Each year, it enables twelve Ph.D.s up to five years “to undertake two-year fellowships without any of the usual obligations of teaching and university administration” and is a program of the Robert Wood Johnson Foundation. The fact that RWJF is the largest foundation in the world funding societal policies against obesity, smoking and alcohol, we are to believe, does not constitute a potential conflict of interest.

This is exactly why any time I read about a scientific study that gets lots of media play I always get somewhat cynical about it. Not because I want to bash the media exactly (not every reporter in the world can have an advanced degree in science) but when studies get a lot of attention few media outlets have the time or ability to evaluate whether the science is good or whether the conclusions are validated by their research. That always comes later, by their peers. Long after you've heard some jackass on the radio talk about this study which he only heard third-hand anyway from his 19-year-old producer's assistant who read the headline on google news.