Weight Maven

Argh. Via Stephan Guyenet on Twitter comes a nearly year-old study about the rise in morbid obesity (BMI greater than 40).

Here’s part of the abstract (emphasis mine):

Between 2000 and 2010, the prevalence of a BMI >40 kg m−2 (type III obesity), calculated from self-reported height and weight, increased by 70%, whereas the prevalence of BMI >50 kg m−2 increased even faster. … The growth rate appears to have slowed down since 2005.

And here’s what I find annoying: the journal titled the report “Morbid obesity rates continue to rise rapidly in the United States.”

I guess “Morbid obesity rates continue to rise rapidly in the United States except since 2005″ was too long to tweet!

BTW, one of the things that makes this rise “rapid” is that rise is a relative measure, and morbid obesity was fairly rare at the start of their measurement period (mid-1980s). In terms of absolutes, the authors estimate that the actual percent of the population that are morbidly obese is just under 7 percent (6.6).

This kind of measurement is statistically valid, but it can be misleading (think “lies, damned lies, and statistics.” It’s like those reports that say something like if you have a 1% chance of heart disease and you drink, you now have a 3% chance. That doesn’t sound so bad, but of course, the media will report it as “Have one drink, increase your chance of heart disease by 3 times!”

You may well decide that a life without alcohol (or chocolate or red meat or whatever the substance du jour is) is worth decreasing your risk, but you may decide that the cure is worse than the disease ;).

Anyways, I’ve got no real issue with the study. It’s pretty intuitive that more people are morbidly obese today than they were 25 years ago. But based on the authors’ findings, I find the title misleading *and* annoying.