Saturday, March 3, 2012

The Monkey Meat and Book Diet: Debunking Associations

The latest issue of The Wilson Quarterly has a the elements of a plan for losing weight: monkey meat and reading. Journalist Scott Wallace, on an assignment with National Geographic, trekked through the Amazon eating "nothing but monkey meat for days on end, losing 30 pounds on the journey."(1)

That's not all--the magazine adds that reading is associated with lower BMI (body mass index). "In particular, readers are less likely to be overweight than TV watchers. Indeed, regular book-reading seems to predict lower BMI about as reliably as regular exercise."(2) (The article cites a forthcoming paper by Fred C. Pampel  in Sociology of Health and Illness.) "Pampel found that education, employment, and other components of socioeconomic status correlate with body mass index (BMI)."

I'm going with reading because it's easier than raising your socioeconomic status. You'll have to source the monkey meat yourself, though. I can't solve all your problems for you.

Of course, I'm kidding. While nearly anyone would lose weight eating a very low carb diet of monkey meat while hiking the Amazon, you need a diet you can live with for the rest of your life. (And just because one person has success with a diet doesn't mean you will. Remember the Twinkie guy and the potato guy?)

As a public policy scholar, Mr. Wallace, who lost 30 pounds, must read a book now and then, yet he had 30 pounds available to lose. Obviously, reading doesn't cause weight loss, it's just associated with normal weight. Association isn't causation. A might cause B, B might cause A, or something else might cause both. What isn't so obvious is associations between diet and weight, exercise and weight, or drugs and health outcomes. It's commonly assumed that "healthy lifestyles" like exercising and eating right cause normal weight and good fitness. But do they? Or are healthier people more likely to exercise, health-minded people more likely to take their pills, and health buffs more likely to follow the latest advice on diet? We're all prone to seeing patterns even where there aren't any--and association is a type of pattern.

In the book Proofiness, Charles Seife writes,
Casuistry--without the extra "u"--is the art of making a misleading argument through seemingly sound principles. Causuistry is a specialized form of casuistry where the fault in the argument comes from implying that there is a causal relationship between two things when in fact there isn't any such linkage.
Causuistry is particularly common in health and nutrition research; you might have even altered your diet because of it.(3)
Seife goes on to debunk the link between Nutrasweet and brain tumors.
Sure, Nutrasweet consumption was going up at the same time brain tumor rates were, but a lot of other things were on the rise too, such as cable TV, Sony Walkmen, Tom Cruise's career.(4)
Comedian Tom Naughton gave a speech called "Science for Smart People"(5) that covered associations. Watch it, and you may never think about health and nutrition news the same way again. (ETA: I referenced the wrong video before.)

1. "Avoiding the Arrow People," The Wilson Quarterly, February 1, 2012.
2. "Paper Treadmills" by Stephen Bates, The Wilson Quarterly, February 1, 2012.
3. Proofiness by Charles Seife, p. 44. Penguin Books, 2010.
4. Ibid, p. 46.
5. "Science for Smart People" by Tom Naughton, 2011.

No comments: