(New York Times, hat tip Bobby)
ACCORDING to the United States government, nearly 7 out of 10 American adults weigh too much. (In 2010, the Centers for Disease Control and Prevention categorized 74 percent of men and 65 percent of women as either overweight or obese.)
But a new meta-analysis of the relationship between weight and mortality risk, involving nearly three million subjects from more than a dozen countries, illustrates just how exaggerated and unscientific that claim is.
The meta-analysis, published this week in The Journal of the American Medical Association, reviewed data from nearly a hundred large epidemiological studies to determine the correlation between body mass and mortality risk. The results ought to stun anyone who assumes the definition of “normal” or “healthy” weight used by our public health authorities is actually supported by the medical literature.
The study, by Katherine M. Flegal and her associates at the C.D.C. and the National Institutes of Health, found that all adults categorized as overweight and most of those categorized as obese have a lower mortality risk than so-called normal-weight individuals. If the government were to redefine 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 re-categorized as normal weight instead.
To put some flesh on these statistical bones, the study found a 6 percent decrease in mortality risk among people classified as overweight and a 5 percent decrease in people classified as Grade 1 obese, the lowest level (most of the obese fall in this category). This means that average-height women — 5 feet 4 inches — who weigh between 108 and 145 pounds have a higher mortality risk than average-height women who weigh between 146 and 203 pounds. For average-height men — 5 feet 10 inches — those who weigh between 129 and 174 pounds have a higher mortality risk than those who weigh between 175 and 243 pounds.
Now, if we were to employ the logic of our public health authorities, who treat any correlation between weight and increased mortality risk as a good reason to encourage people to try to modify their weight, we ought to be telling the 75 million American adults currently occupying the government’s “healthy weight” category to put on some pounds, so they can move into the lower risk, higher-weight categories.