Every week seems to bring a new study about the economics of obesity, but it’s rare for a top scholar in the field to piece it all together for a general audience. John Cawley, who directs Cornell University’s Institute on Health Economics, Health Behaviors & Disparities, has done just that in the latest issue of the National Bureau of Economics Research Reporter. Here are 13 statements—some controversial—from his article, which draws on dozens of studies by himself and others:
1. About 2.8 million people a year die from excess weight worldwide.
2. Body mass index, which is based only on height and weight and ignores fat, misclassifies some muscular people as obese and some unmuscled people as not obese.
3. The black-white gap in obesity among women is only half as large if obesity is defined as a percentage of body fat rather than high BMI.
4. The rise in obesity began 10 to 20 years earlier if obesity is measured by skinfold thickness rather than BMI.
5. Obesity raises annual medical costs by $2,741 (in 2005 dollars).
6. Obesity accounted for about 21 percent of national health spending in 2005.
7. There is little evidence that income affects weight, but weight seems to affect income.
8. For white women, whose incomes are most affected, being 64 pounds heavier is associated with 9 percent lower wages. Some studies “suggest that discrimination plays an important role.”
9. Excess weight is now the primary reason that applicants to the military are rejected.
10. There is no evidence that increases in physical education requirements for school children have any impact on youth weight. It doesn’t even increase physical activity for high school boys.
11. It’s possible that for some young people, increased physical education increases muscle and decreases fat with little net effect on weight.
12. People who were offered financial rewards in a workplace weight-loss program didn’t lose more weight than a control group. Those with some of their own money at stake lost two pounds more than the controls.
13. There is “very little, if any, evidence” that over-the-counter weight-loss products are effective. Some are dangerous.
Cawley, who got his economics Ph.D. at the University of Chicago, edited the Oxford Handbook of the Social Science of Obesity, a book you probably didn’t know existed. According to the Reporter, Cawley (profile pic here) is married to a fellow Cornell economist, Rachel Dunifon, and “in his spare time, he enjoys watching hour-long TV dramas with his wife and trying not to cheer too [loudly] at his sons’ soccer games.”