You think you know what’s fat, don’t you? It’s defined by pounds, or body-mass index, or how much roly-poly flesh you can pinch between your thumb and forefinger. (Try this only on yourself.) You know fat when you see it. And you can measure it, objectively. Right? And way too many people are way too tubby, right?
Not so fast, calorie-counter. We have new research and it looks like our estimates of the number of fat people might be overinflated. Bloated. Turns out the people we thought were fat might actually be healthier than the people we thought were normal weight. So if that’s healthier, shouldn’t it be the norm?
Specifically, people who are nominally “overweight”—the 30 percent of the U.S. population with a body-mass index of 25 to 30—have a 6 percent lower risk of death than people who are “normal weight,” with a BMI of 18.5 to 25. After looking at almost 100 studies involving nearly three million people, researchers claim the “findings are very consistent across all different ages and continents,” according to the Wall Street Journal’s report.
Author and professor Paul Campos, writing in the New York Times, states the obvious statistical conclusion: “If the government were to redefine a ‘normal weight’ as one that doesn’t increase the risk of death, then about 130 million of the 165 million American adults currently categorized as overweight and obese would be recategorized as being of normal weight instead.”
So…whoa. One big meta-study and the obesity epidemic is wiped away?
Not so fast, Dove Bar-scarfer. “Observational studies merely record statistical correlations,” Campos says. No one knows that extra weight makes you healthier. Maybe rich people—who have better health care generally—also eat creamier ice cream, and that’s what’s going on here. Maybe the thin group has a higher percentage of people who have lost weight due to sickness, and that makes them more likely to cork off.
And maybe more important, we are obtuse about obesity measurements.
As the Journal says: “BMI is an inexact measure of health—largely because it doesn’t differentiate between fat and muscle mass. Many athletes are technically obese, based on BMI, even though they are extremely fit.” BMI also doesn’t differentiate between so-called bad fat (like that spare tire around your middle) and other kinds of fat that are not, statistically, as bad for you.
Bottom line: pay less attention to your BMI. Pay more attention to that slab of flan riding on top of your abs.
Painting: Without Ceres and Bacchus, Venus cools (1614), by Peter Paul Rubens, via Wikimedia Commons
