About half of the world now lives in cities, and this figure is expected to grow to 70 percent by 2050, with most urban growth projected to occur in developing countries. As people move to cities at this unprecedented pace and scale, they face altered lifestyles, behaviors and economic circumstances, many of which are contributing to a global health crisis of obesity. In developed countries, one out of every two people is overweight or obese, and the trend is moving to poorer countries.

In Latin America, there’s a greater prevalence of obesity in cities.  There are also estimates in India that 50 percent of urban woman are obese compared to 20 percent of rural women. In Hong Kong, “general obesity rates among primary-school students climbed to 22.2% in 2009-2010, from 16.7% in 1996-1997,” according to the Wall Street Journal. And childhood obesity rates in China’s coastal cities have grown 20-fold since 1985.  (In Mexico, on the whole, 70 percent of the population is overweight and 30 percent is obese. The United States is not far behind, with 68 percent of people overweight and 28 percent obese.)

As urbanization occurs alongside these rising obesity rates, this presents an opportunity to change people’s behaviors through sustainable urban design, active transport, and policies that encourage physical activity and other healthy ways to live in cities. 

GROWING PROBLEM

There are many reasons for expanding waistlines, but the behavioral and lifestyle changes that come as a result of  rural-to-urban migration are key contributors. In cities, the increased consumption of low-cost and accessible processed foods has supplanted more traditional diets that offer a better micronutrients. There are also disparities in access to food, sometimes resulting in urban “food deserts,” where food supermarkets are rare, understocked or overpriced, which further encourages or necessitates the need to drive a car in order to eat healthy food. Food advertisements, also more prevalent in cities, are targeted specifically at children, literally feeding the addiction to unhealthy food. What’s more, city life can more often mean a family of two income earners that have less time to prepare food for their families.

The transition away from physical labor, too, results in a loss of physical activity and weight gain. But even in rural areas, the rise in obesity is a problem. Farmers, for instance, who use mechanical farm equipment and may grow one type of crop as opposed to a diversity of vegetables, live in isolated areas where there is often easy access to highly processed food.

Obesity used to be associated with affluence but now there is no clear correlation in the developing world, as the foods highest in fats and sugar have become so widespread. Rebecca Kanter, a Ph.D. candidate at John Hopkins Bloomberg School of Public Health, conducted field research on obesity in Mexico and Brazil between 2007 and 2009. “At least in these two countries obesity rates are rising among all socioeconomic groups, not just the poor,” she says. “Historically, the way the pattern worked in many developed countries is that overweight/obesity would increase  among the upper classes first and then increase more rapidly among the poor as the most low cost and convenient foods are those that are highest in fats and sugars and thus, inherently, also high in calories.”

The number of overweight individuals now rivals the number of underfed people on the globe. The irony of obesity is that “while some of the poor are becoming plumper, they are not necessarily better fed,” says the Food and Agriculture organization of the United Nations.  “Obesity often masks underlying deficiencies in vitamins and minerals.”

WEIGHING OTHER OPTIONS

The global health crisis of obesity can be alleviated with active forms of transit, specifically biking and walking, and sustainable urban design, that promotes density and transit-oriented development. Such lifestyles can help prevent, reduce or stabilize excess weight gain by increasing energy expenditure, says Kanter. They also tend to make people feel safer and more socially connected—both factors that contribute to an overall healthier lifestyle.

In TheCityFix, we’ve written about a few of these initiatives:

• Encouraging physical activity for children. In Lecco, Italy, parents and staff lead chaperoned walks, known as the Piedibus, to make children feel safe walking from home to school and also to encourage physical activity, similar to the Safe Routes to School initiative in the United States. First Lady Michelle Obama also recognizes the importance of “active community design,” as promoted through her national Let’s Move! campaign. And the French have a national obesity prevention initiative called Epode, focused on healthy eating and physical activity.
• Hosting car-free days. These auto-less events, gaining popularity in cities around the world, force people to reconsider their relationship to the car. As an example of a more prolonged attempt to keep people out of their cars, the city of Arlington, Va. launched the Car-Free Diet campaign, which provides drivers with a calculator to see how many calories they burn, dollars they save, and CO2 emissions they reduce by following a car-free diet.
• Banning junk food. City officials in California banned the construction of any new fast food drive-thrus, in an attempt to deter people from “in-car dining” culture, which contributes to congested roads and clogged arteries.