The Obesity Epidemic

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Science  04 Jun 2004:
Vol. 304, Issue 5676, pp. 1413
DOI: 10.1126/science.304.5676.1413

There is a growing public health crisis that is global in scope, and it isn't another emerging infectious disease. It concerns being overweight and the adverse health consequences of obesity, which include diabetes, heart disease, and cancer. To sketch the extent of this problem, we begin with the United States, an appropriate starting point because U.S. dietary styles and food habits have been exported so widely around the world.

In 1998, the National Institutes of Health (NIH) in the United States found that 97 million U.S. adults (55% of the U.S. population) were considered obese or overweight. The Surgeon General issued a “Call to Action” on the obesity problem, but it drew a lackluster response from the responsible federal agencies, and Americans continued to consume an average of 3800 calories per person per day, or about twice the daily requirement. It is now estimated that over two-thirds of U.S. adults are overweight. Last year, NIH Director Elias Zerhouni appointed an agency-wide task force to develop recommendations for coping with the epidemic, and perhaps that gives room for some encouragement.

But this is an exploding health issue in Europe as well as the United States. Nor is it limited to the developed world: Mayans in Guatemala, South Africans, aboriginal Australians, and Pacific Islanders also show patterns of emerging obesity. The World Health Organization (WHO) is deeply concerned about the issue, recognizing that nearly 1 billion adults are overweight and at least 300 million are obese. It has developed a plan that nations might use to deal with this health crisis. After more than 2 years of intensive debate among world countries, WHO formally approved a Global Strategy on Diet, Physical Activity and Health in May 2004 that recommends that people limit their intake of fats, salt, and sugar. This strategy had been heavily criticized by officials of the U.S. Department of Health and Human Services (HHS), despite Secretary Tommy Thompson's high-profile obesity initiative that even included his own weight-loss program! The HHS critique supported an effort by the U.S. delegation to force major revisions in the WHO plan related to advertising and food pricing. An HHS official, who apparently believes that economic incentives don't matter, said that WHO should stick to “sound science.”

In this space over a year ago (Science, 7 Feb. 2003, p. 781), Marion Nestle of New York University was critical of the food industry for its political influence over U.S. food policy and for its aggressive marketing of foods that are high in energy but low in nutritional value. Every once in a while, a representative for that industry says something that is unconsciously revealing. In responding to reporters' queries about the WHO plan, a spokesperson suggested that more attention be given “to the issue of individual responsibility.” That neatly displaced a burden from manufacturers, advertisers, and government, and put it on the sufferer.

Well, behavioral modification may be the solution for some, but for others the issue may be biochemical, not behavioral. Work on the genetics of obesity and on the biochemical relations between leptin and other molecules that signal the feeding centers of the brain may bring more help to those who want to lose weight but somehow can't. In the past, the urge for weight loss has led ambitious dieters into medical perils even more serious than staying overweight. Fad diets in the 1970s featuring high-protein liquids derived largely from animal collagen caused deaths from cardiac causes among young women until they were forced off the market. Fortunately, there were, and still are, alternatives; reasonable exercise and thoughtful choices among a balanced variety of foods help. Perhaps the most provocative news from the laboratory is that calorie restriction in some organisms promotes longevity, even if started late in life.

The obesity problem demands serious action from governments because it is levying heavy costs on societies everywhere. WHO has clearly raised the bar with its endorsement of a global campaign against obesity. At the political level, the best solution surely is a ministry or department that is responsible for dietary advice, research, and food policy and is dominated by the interests of consumers rather than producers. In the United States, such responsibility is irrationally divided between the Public Health Service and the producer-oriented Department of Agriculture—an arrangement that other governments would be wise not to copy.

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