Preventive Medicine Column
Dr. David L. Katz
According to a recent NY Times Op-Ed by Paul Campos, a law professor at the University of Colorado, our “fear” of fat- namely epidemic obesity- is, in a word, absurd. Prof. Campos, the author of a book entitled “The Obesity Myth,” who has established something of a cottage industry for some time contending that the fuss we make about epidemic obesity is all some government-manufactured conspiracy theory, or a confabulation serving the interests of the weight loss-pharmaceutical complex, was reacting to a meta-analysis, published last week in JAMA, indicating that mortality rates go up as obesity gets severe, but that mild obesity and overweight are actually associated with lower overall mortality than so-called “healthy” weight.
This study- debunked for important deficiencies by many leading scientists around the country, and with important limitations acknowledged by its own authors- was treated by Prof. Campos as if a third tablet on the summit of Mount Sinai.
Treating science like a Ping-Pong ball is what is absurd. It’s also scary- as is the obesity epidemic.
As for the meta-analysis, a study designed to pool the results of other studies, the first, obvious limitation is that it examined mortality (death) but not morbidity (illness). The Global Burden of Disease Study, recently published in The Lancet and sponsored by the World Health Organization, the World Bank, and the Bill and Melinda Gates Foundation, is widely acknowledged as one of the most comprehensive epidemiologic assessments in history. What it shows, among countries around the world, is that we are living longer, but sicker- and that obesity is one of the important reasons for the latter. Thanks to the cutting edge of biomedical advance, we can often forestall death; but high tech medicine is not remotely as useful for cultivating health and vitality.
When people get sick, they generally lose weight. The new study was in no way adjusted to exclude from the analysis people who were thin because they were sick. We have long had evidence that among older people, hanging on to weight is associated with better outcomes than losing weight. There is, as well, an enormous difference between being lean because of eating well and being physically active, and being lean because of anorexia nervosa or routine cocaine use. The meta-analysis was blind to any such distinctions.
And there is the fact that while overall obesity rates in the U.S. are showing signs of stabilizing, the rate of severe obesity- the very variety even this meta-analysis associates with a 30% or more increase in mortality risk- is “skyrocketing.”
The evidence that obesity is genuinely harmful much (though certainly not all) of the time is both vast, and incontrovertible. As noted, the Global Burden of Disease report indicates that mortality is not the real menace- it’s morbidity. Obesity is consistently, powerfully associated with the risk of chronic disease. When I was in medical school, we learned about “adult onset” diabetes. That is now called “type 2” diabetes because it occurs routinely in kids as well. It occurs routinely in kids because of epidemic childhood obesity.
The CDC is projecting that by mid-century, up to 1 in 3 Americans will be diabetic, due almost entirely to epidemic obesity. The trend is already well under way. For those doubting, as Prof. Campos seems to, that obesity is the cause of all this diabetes and chronic disease, there is the Diabetes Prevention Program– which demonstrates that a 7% loss in body weight produces a 58% reduction in the development of diabetes among high-risk adults. Studies spanning 20 years show a decisive association between healthful lifestyle practices, with resulting weight control, and a dramatic reduction in both chronic morbidity and premature mortality.
Unlike Prof. Campos, who is a lawyer, I am a doctor- I take care of patients, including those wrestling with weight control. Over 20 years, I have seen personally the changes in health and vitality when people who are obese become lean through the application of sensible and sustainable lifestyle practices.
The new meta-analysis may suggest that the range of ‘normal’ for weight could be expanded, although it by no means proves it. But at the population level, epidemic obesity is decisively established as a clear and all-but-omnipresent danger. It is absurd to suggest otherwise. And it’s those who do so, who play Ping-Pong with science because of misguided bias or motivated self-interest -who threaten to forestall the societal action needed to turn this toxic tide. I find that pretty scary.
Dr. David L. Katz; www.davidkatzmd.com