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An Epidemic of Obesity Myths
Myth: Obesity Will Significantly Shorten Life Expectancy

"Olshansky now says … his life expectancy forecasts might be inaccurate." Science, 2005
Life Expectancy in the United States

In 2002, Dr. William Klish of Texas Children's Hospital told the Houston Chronicle: "If we don't get this epidemic [of childhood obesity] in check, for the first time in a century children will be looking forward to a shorter life expectancy than their parents." Since then, Klish's statement has entered the lexicon of obesity scaremongers, making its way into countless articles, editorials, and even Congressional testimony—all without so much as a shred of credible research to back it up. Klish himself told the Center for Consumer Freedom that while he is the source of this pessimistic prognostication, his claim does not come from "evidence-based research." Rather, he explained: "It's based on intuition."

On March 17, 2005, more than three years after Klish first suggested the theory, The New England Journal of Medicine released a deeply flawed but highly publicized study that appeared to justify Klish's assertion. It claimed that because of obesity, the "youth of today may, on average, live less healthy and possibly even shorter lives than their parents." But like Klish, Dr. S. Jay Olshansky and his co-authors admitted that their dire prediction relied on their "collective judgment" rather than empirical, scientific evidence.

In May 2005, Science magazine published an article on the controversy over obesity deaths following the publication of a paper by Dr. Katherine Flegal and co-authors that said the number of deaths from excess weight was just one-fifteenth what the CDC said it had been. In the article, Olshansky appeared to back off his conclusions about life expectancy. According to Science:
"Olshansky now says that in light of Flegal's recent paper on obesity deaths and a companion paper that she, Williamson, and other CDC scientists authored in the same issues of JAMA, his life expectancy forecasts might be inaccurate."
Even before the Flegal study, Olshansky had more than his share of critics. "The Olshansky piece is seriously flawed," explained Dr. James Vaupel, director of the Max Planck Institute for Demographic Research in Germany. "His perspective is that of an advocate making a case rather than a scientist evaluating the body of conflicting evidence."

Vaupel isn't alone in questioning Olshansky's original prediction. Dr. Robert N. Anderson, the lead author of the CDC's National Vital Statistics Report on life expectancy, explained that he was extremely skeptical of Klish's and Olshansky's claim about obesity's effect on life expectancy. He told the Center for Consumer Freedom: "I really would be shocked if we got a generation down the road and life expectancy was lower than the previous generation. I really would be surprised … We've never seen anything like that. Life expectancy has gone up pretty steadily." Even noted obesity scaremonger JoAnn Manson, who is profiled later in this report and is one of the few scientists to criticize the Flegal study, told the Associated Press: "the calculations that were made may not be perfect." So what went wrong with Olshansky's study? Although he purports to show that if the entire nation were an "ideal" weight we might live, on average, a few months longer, he provides no empirical research to back up his foreboding forecast about life expectancy actually decreasing. Instead, without so much as a footnote (except to their own work), he and his co-authors muse that the "trends" in the data suggest the possibility of life expectancy declining.
"These are just back-of-the-envelope, plausible scenarios. We never meant for them to be portrayed as precise."
-Study co-author David Allison in Scientific American, June 2005