Science The link between weight and health appears more complex than we thought | Daniel James Devine
In terms of personal weight, the chances are slim you carry around what U.S. health officials call a “normal” figure. According to surveys the Centers for Disease Control and Prevention (CDC) conducted in 2009 and 2010, fewer than 1 in 3 Americans are either normal weight or underweight. The rest—two-thirds of adults ages 20 and up—are said to be “overweight” or “obese.”
Health experts have been warning about this pandemic of fat for years. They point to studies showing that being overweight or obese increases the risk of cancer, stroke, infertility, heart disease, sleep apnea, diabetes, and other health problems.
But in a large-scale review of health data, published in the Journal of the American Medical Association in January, CDC researchers stumbled upon counterintuitive results: People in the government’s “overweight” category actually have a lower chance of dying prematurely than those of normal weight. The risk of mortality from all causes is 6 percent less among the overweight. And those with “grade 1” obesity (the lowest level on the obesity spectrum) are at no more risk than the normal-weight folks. Only people with grades 2 or 3 obesity have significantly higher risks.
Those findings are in line with some studies indicating patients with certain conditions, such as heart disease, may be more likely to survive treatment if they carry more weight. Experts call it the “obesity paradox.”
What’s unclear is how overweight or obese people can be more likely to get diseases yet less likely to die from them. Doctors have suggested that overweight people may be quicker to get medical attention when they encounter health problems—or that extra fat enables the body to weather prolonged illness or surgery.
At least one health expert, Walter Willett of the Harvard School of Public Health, sharply criticized the new CDC review, calling it “rubbish.” He said other studies that take into account risks among normal-weight people, such as smoking, do show that mortality risk grows alongside weight.
The statistics are confusing because many variables—smoking, exercise, stress, diet—together influence health: It isn’t simply fat that makes you sick. Also, the body mass index—a height-to-weight ratio the government uses as a measuring stick for flab—is used in weight studies, but can’t distinguish between fat and muscle. Thus, the BMI ranks former bodybuilder Arnold Schwarzenegger and Dallas Cowboys quarterback Tony Romo as overweight or even obese.
Perhaps it’s time to revise the government’s weight labels. The term “overweight” implies that a person needs to shed a few pounds to become healthier. That may not always be true.
The U.S. Food and Drug Administration in January published draft rules related to a food safety overhaul Congress passed in 2010 in response to several food poisoning outbreaks. The proposed rules could make peanuts, tomatoes, cantaloupes, or other produce less likely to host dangerous contaminants like E. coli or listeria—but could also increase their cost. Farmers would have to ensure irrigation water that touches fruits and vegetables is microbiologically safe, and provide portable toilets for farmhands. Food processing plants would have to improve recordkeeping and eliminate possible entry points for contamination. The total changes could cost the food processing industry $475 million a year, and individual large farms $30,000 a year. —D.J.D
Copyright © 2013 God’s World Publications, Feb. 9, 2013, Vol. 28, No. 3