Jeffrey M. Friedman is my fat science hero!
There’s this argument I reference quite a bit about humans naturally coming in a range of shapes and sizes because of genetic diversity. It’s my “weight distribution curve” argument.
I first learned about the weight distribution curve when I read this post on JunkFoodScience.com: Obesity statisticulation — When will people get it?
Even before I got into FA, I was aware that statistics can be manipulative. And I’m certainly not immune to it. If I stare too long at the CDC statistics saying that in 1980 the obesity rate was 15% and now it’s up to 27% I’ll have a flash of FA doubt.
The argument made by the JFS post says if you plot BMI by population, the SHAPE of the weight distribution curve hasn’t really changed over time. It’s just shifted over a bit.
I really like that argument and I use it a lot, but I have to admit there’s always been a little doubt at the back of my brain that one day I’m going to learn some new concept about statistics that would show me the flaw in that argument.
It’s important to me that I don’t just parrot information. I want to make sure that what I’m saying has a sound basis. But I’m not trained as a statistician. I’m doing my very best to understand epidemiological concepts, but there is always the chance that I’m missing some part of the big picture.
So, this week we’ve been talking about the HHMI 2004 Holiday Lectures about Obesity. I’m watching Lecture 1, Deconstructing Obesity, by Jeffrey M. Friedman, M.D., Ph.D. and it comes to the part where he says,
…there’s a known phenomenon in in epidemiology when you have a fixed threshold for a trait, a small shift in the average value has a disproportionate effect on the number of people who exceed the threshold.
And I felt a sense of relief wash over me. It brings two concepts together: how it can be that the shape of the weight distribution curve hasn’t changed that much over time but the rate of obesity has has doubled.
The funny part? In the original JFS article — the one that informed me about the weight distribution curve—heavily featured quotes from an NPR interview of Jeffrey M. Friedman.
Of the four lectures about obesity, the first one was my favorite. I think Jeffrey M. Friedman totally kicks ass. He explains the complex issue of weight clearly and in a way that made sense to me. His lecture reaffirmed stuff I already knew and taught me some new stuff, too!