Science & Technology

Obesity Researchers Outraged by Inconvenient Truth About Weight and Mortality


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Since 2005, when Katherine Flegal of the National Center for Health Statistics began reporting that people whom the government deems "overweight" appear to be healthier than people who stay within the recommended weight range, her work has provoked outrage from other obesity researchers. As Virginia Hughes explains in a recent Nature feature story, the critics' main complaint is not that Flegal's findings are wrong but that they are unhelpful. Hughes describes the reaction to a meta-analysis of 97 studies that Flegal and her colleagues published last January in The Journal of the American Medical Association, which found that mortality rates were lowest among people considered overweight but not obese:

The result seemed to counter decades of advice to avoid even modest weight gain, provoking coverage in most major news outlets—and a hostile backlash from some public-health experts. "This study is really a pile of rubbish, and no one should waste their time reading it," said Walter Willett, a leading nutrition and epidemiology researcher at the Harvard school, in a radio interview. Willett later organized the Harvard symposium—where speakers lined up to critique Flegal's study—to counteract that coverage and highlight what he and his colleagues saw as problems with the paper….

Studies such as Flegal's are dangerous, Willett says, because they could confuse the public and doctors, and undermine public policies to curb rising obesity rates. "There is going to be some percentage of physicians who will not counsel an overweight patient because of this," he says. Worse, he says, these findings can be hijacked by powerful special-interest groups, such as the soft-drink and food lobbies, to influence policy-makers.

Other researchers take a less result-oriented approach:

Many scientists say that they are uncomfortable with the idea of hiding or dismissing data—especially findings that have been replicated in many studies—for the sake of a simpler message. "One study may not necessarily tell you the truth, but a bulk of studies saying the same thing and being consistent, that really is reinforcing," says Samuel Klein, a physician and obesity expert at Washington University in St Louis, Missouri. "We need to follow the data just like the yellow brick road, to the truth."…

[Flegal] says that the public's reaction to her results is not her primary concern. "I work for a federal statistical agency," she says. "Our job is not to make policy, it's to provide accurate information to guide policy-makers and other people who are interested in these topics." Her data, she says, are "not intended to have a message."

An editorial in the same issue of Nature questions Willett's intemperate criticism of Flegal as well as his preference for clear messages even when muddier ones are closer to the truth: 

It is easy to see why those who spend their lives trying to promote the health of others gnash their teeth when they see complex findings whittled down to a sharp point and used to puncture their message. It is more difficult, from a scientific perspective, to agree that these findings should not be published and discussed openly, warts and all, purely because they blend uncertainty into a simple mantra. Make things as simple as possible, Einstein said, but no simpler. And simple, black-and-white messages can cause confusion of their own. All things in moderation—and that should include the language we use.

[via Trevor Butterworth at Forbes