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Chapter 9. Redesigning Cities for People: Urbanization and Obesity
Until recently, the principal link between urbanization and health was air pollution, but now this is changing as obesity spreads, eclipsing air pollution as a health threat. One consequence of urbanization, particularly when it is auto-centered, is the lack of opportunity for walking, cycling, and other forms of exercise. Exercise deprivation and dietary excesses together often translate into weight gain. As a result, obesity—which is concentrated in cities—is reaching epidemic proportions worldwide. No longer confined to the industrial world, obesity is emerging as a leading global public health issue. In both China and Indonesia, for instance, the incidence of obesity in cities is double that in the countryside. In the Congo, it is six times higher.22
Obesity is afflicting a growing number of people in industrial and developing countries alike. It is damaging human health—raising the incidence of heart disease, stroke, breast cancer, colon cancer, arthritis, and adult onset diabetes. In the United States, the Centers for Disease Control and Prevention estimates that 300,000 Americans now die prematurely each year from obesity-related illnesses.23
In recent years, efforts to reduce obesity have focused on lowering caloric intake to the level of caloric use by dieting, as the perpetual presence of diet books on bestseller lists in industrial countries indicates. Unfortunately, this can be physiologically difficult given the abnormally low calorie burning associated with sedentary life-styles. Ninety-five percent of Americans who attempt to achieve a healthy body weight by dieting alone fail, largely because exercise deprivation is also contributing to obesity. With metabolic systems shaped by millions of years of highly active hunting and gathering, many people may not be able to maintain a healthy body weight without regular exercise.24
For the first time in history, a majority of adults in some highly urbanized societies are overweight. In the United States, this applies to 61 percent of all adults. In Russia, the figure is 54 percent; in the United Kingdom, 51 percent; and in Germany, 50 percent. For Europe as a whole, more than half of the adults between 35 and 65 years of age are overweight. The numbers are rising in developing countries as well. In Brazil, for example, 36 percent of adults are overweight.25
Not only are more people overweight than ever before, but their ranks are expanding at a record rate. In the United States, obesity among adults increased by half between 1980 and 1994. Among Americans, 20 percent of men and 25 percent of women are more than 30 pounds (13.6 kilograms) overweight. Surveys in China showed that during the boom years of the early 1990s, the share of adults who were overweight jumped from 9 percent to 15 percent.26
Juvenile obesity is rising rapidly too. In the United States, where at least 1 out of 10 youngsters 6 to 17 years of age is overweight, the incidence of obesity among children has doubled over the last generation. Not only does juvenile obesity typically translate into adult obesity, but it also causes metabolic changes that make the disease difficult to treat in adulthood.27
In a Worldwatch Paper entitled Underfed and Overfed, Gary Gardner and Brian Halweil report that the number who are overnourished and overweight has climbed to 1.1 billion worldwide, rivaling the number who are undernourished and underweight. Peter Kopelman of the Royal London School of Medicine summarizes medical thinking: "Obesity should no longer be regarded simply as a cosmetic problem affecting certain individuals, but [as] an epidemic that threatens global well being."28
Damage to health from obesity takes many forms. In addition to the illnesses noted earlier, heavier body weight increases resistance to the heart's pumping of blood, elevating blood pressure. It also raises the stress on joints, often causing lower back pain. People who are obese are four times as likely to have diabetes as those who are not.29
As weight goes up, life expectancy goes down. In analyzing this relationship for Americans between the ages of 30 and 42, one broad-based study found that the risk of death within 26 years increased by 1 percent with each additional pound (0.45 kilograms) of excess weight.30
The estimated 300,000 Americans who die prematurely each year as a result of being overweight compares with the 400,000 who die prematurely from cigarette smoking. But there is one difference. The number of cigarettes smoked per person in the United States is on the decline, falling some 42 percent between 1980 and 2000, while obesity is on the rise. If recent trends continue, it is only a matter of time before deaths from obesity-related illnesses in the United States overtake those related to smoking.31
Gaining weight is a result of consuming more calories than are burned. With modernization, caloric intake has climbed. Over the last two decades, caloric intake in the United States has risen nearly 10 percent for men and 7 percent for women. Modern diets are rich in fat and sugar. In addition to sugars that occur naturally in food, the average American diet now includes a staggering 53 teaspoons of added sugar a day, much of it in soft drinks and prepared foods. Unfortunately, diets in developing countries, especially in urban areas, are moving in this same direction.32
While caloric intake has been rising, exercise has been declining. The latest U.S. survey shows that 57 percent of Americans exercise only occasionally or not at all, a number that corresponds closely with the share of the population that is overweight.33
Economic modernization has systematically eliminated exercise from our lives. Workers commute by car from home to work in an office or factory, driving quite literally from door to door. Automobiles have eliminated daily walking and cycling. Elevators and escalators have replaced stairs. Leisure time is spent watching television. In the United Kingdom, the two life-style variables that correlate most closely with obesity are television viewing and automobile ownership.34
Children who watch television five or more hours a day are five times as likely to be overweight as those who watch less than two hours a day. Time spent playing computer games and surfing the Internet in lieu of playing outside is also contributing to the surge in obesity.35
Another manifestation of diet failures is the extent to which people are turning to liposuction to remove body fat. Resorting to this surgical procedure, which vacuums out fat from under the skin, is a desperate last measure for those whose diets have failed. In 1998, there were some 400,000 liposuction procedures in the United States.36
For many of those who are overweight, achieving a healthy body weight depends on both reducing caloric intake and burning more calories through exercise. Metabolically, we are hunter-gatherers. Given our heritage, exercise may be a genetic imperative.
Restoring exercise in our daily lives will not be easy. Today's cities, designed for automobiles, are leading to a life-threatening level of exercise deprivation. Our health depends on creating neighborhoods that are conducive to walking, jogging, and bicycling.
The challenge is to redesign communities, making public transportation the centerpiece of urban transport, and augmenting it with sidewalks, jogging trails, and bikeways. This also means replacing parking lots with parks, playgrounds, and playing fields. Unless we can design a life-style that systematically restores exercise to our daily routines, the obesity epidemic—and the health deterioration associated with it—will continue to spread along with urbanization.
22. Barry M. Popkin, "Urbanization and the Nutrition Transition," Achieving Urban Food and Nutrition Security in the Developing World, A 2020 Vision for Food, Agriculture, and the Environment, Focus 3, Brief 7 (Washington, DC: International Food Policy Research Institute (IFPRI), August 2000).
23. William H. Dietz, "Battling Obesity: Notes from the Front," National Center for Chronic Disease Prevention and Health Promotion, Chronic Disease Notes & Reports, winter 2000, p. 2; Ali H. Mokdad et al., "The Continuing Epidemic of Obesity in the United States," Journal of the American Medical Association, 4 October 2000, p. 1650.
24. J.M. Friedman, "Obesity in the New Millennium," Nature, 6 April 2000, pp. 632-34.
25. National Center for Health Statistics, Centers for Disease Control and Prevention (CDC), "Prevalence of Overweight and Obesity Among Adults," www.cdc.gov/nchs/products/pubs/pubd/hestats/obese/obse99.htm, 11 December 2000; Gary Gardner and Brian Halweil, Underfed and Overfed: The Global Epidemic of Malnutrition, Worldwatch Paper 150 (Washington, DC: Worldwatch Institute, March 2000), p. 11; Peter G. Kopelman, "Obesity as a Medical Problem," Nature, 6 April 2000, p. 636; Barry M. Popkin and Colleen M. Doak, "The Obesity Epidemic is a Worldwide Phenomenon," Nutrition Reviews, April 1998, pp. 106-14.
26. Kopelman, op. cit. note 25; World Health Organization, Obesity: Preventing and Managing the Global Epidemic, Report of a WHO Consultation on Obesity (Geneva: 1997).
27. National Center for Chronic Disease Prevention and Health Promotion, "Preventing Obesity Among Children," Chronic Disease Notes & Reports, winter 2000, p. 1.
28. Gardner and Halweil, op. cit. note 25, p. 11; Kopelman, op. cit. note 25, p. 635.
29. Kopelman, op. cit. note 25, pp. 635-43; Ron Winslow, "Why Fitness Matters," Wall Street Journal, 1 May 2000.
30. Kopelman, op. cit. note 25, p. 635.
31. Deaths from smoking from CDC, Targeting Tobacco Use: The Nations' Leading Cause of Death (Washington, DC: 2000); cigarette consumption from USDA, Foreign Agricultural Service, World Cigarette Electronic Database, December 1999, and from USDA, Economic Research Service, Tobacco: Situation and Outlook Report (Washington, DC: April 2001).
32. Winslow, op. cit. note 29; Judy Putnam and Shirley Gerrior, "Trends in the U.S. Food Supply, 1970-97," in Elizabet Frazao, ed., America's Eating Habits: Changes and Consequences (Washington, DC: USDA, Economic Research Service, May 1999), p. 152.
33. Winslow, op. cit. note 29.
34. Kopelman, op. cit. note 25, p. 638.
36. Denise Grady, "Doctor's Review of Five Deaths Raises Concern About the Safety of Liposuction," New York Times, 13 May 1999.
Copyright © 2001 Earth Policy Institute