Why Weight Has Become a Worldwide Problem
Globalization—the inexorable spread of knowledge, technology, culture, and capital from country to country (1)—has been a force both for good and ill, especially when it comes to health. The good: Globalization has lifted millions of people out of poverty, reducing hunger and infectious disease, and, in turn, improving quality of life. The ill: The same social and economic shifts that have increased people’s wealth have also increased their waistlines—and are driving the obesity epidemic in China, India, and other developing countries worldwide.
Many low- and middle-income countries struggle with the so-called “dual burden” of obesity and underweight; but although malnutrition persists in many places, overweight is rapidly becoming a more common problem than underweight. (6) Indeed, for the first time in human history, the world has more overweight than underweight people, (7) and globalization is a major reason for this: It has brought McDonald’s franchises to Mumbai and SUVs to Shanghai, digital TVs to Dar es Salaam and Nestle’s supermarket barges to the Amazon River delta. (8–11) It has thus super-charged the “nutrition transition,” a term for the obesity-inducing shift from traditional to Western diets that accompanies modernization and wealth.
This article gives a brief overview of how globalization is fueling the obesity epidemic in low- and middle-income countries.
At an individual level, obesity results from energy imbalance—too many calories in, too few calories burned. But the food and physical activity choices that individuals make are shaped by the world in which they live:
- The “food environment”—what type of food is available, how much it costs, how it is marketed—influences what people eat.
- The “built environment”—buildings, neighborhoods, transportation systems, and other human-made elements of the landscape —influences how active people are.
- New technologies—cars, computers, televisions, labor-saving devices, and so on—change what people do for work, transportation, and leisure.
Three broad global forces—free trade, economic growth, and urbanization—are rapidly altering people’s food and built environments and spreading new technologies. These macro-level changes are driving the global obesity epidemic, especially in low- and middle-income countries.
Over the past four decades, the price of beef has dropped an astounding 80 percent, thanks in large part to global trade liberalization. (12) Low- and middle-income countries began making it easier to trade crops across country borders in the 1970s and 1980s. (13) In 1994, the General Agreement on Tariffs and Trade formally included agricultural products for the first time, leading to a more open global agricultural marketplace and, ultimately, to cheaper food. (13)
Changes in food prices have been linked to changes in how much people eat, and in turn, their risk of obesity. (14,15) But that’s not the only way that free trade contributes to the problem. Trade liberalization gives people access to different types of food and, often, more high-calorie processed foods. It also removes barriers to foreign investment in food distribution and allows multinational food companies and fast-food chains to expand into new countries. (16)
Due to globalization, the world is getting wealthier, and wealth and weight are linked. (16,17) As countries start to move up the income scale, obesity rates climb, too. Farm workers and poor city-dwellers may now have enough money to pick up “modern habits associated with obesity” (7)—watching television, buying processed foods at supermarkets, and eating more food away from home, for example. But they don’t yet have the healthcare and knowledge about healthy foods and physical activity that would help them keep their weight down. When countries move further up the scale to middle- and high-income, and people have better access to health care and education, obesity rates tend to flatten and fall off.
Interestingly, in low-income countries, wealthier, well-educated people are more likely to be overweight than people who have lower incomes or less schooling. The opposite is true in higher income countries, where wealthier people have lower rates of obesity than the poor. And even in some lower-middle- and middle-income countries, such as China and Brazil, obesity rates are higher or growing more quickly among the poor than among the rich. (18,19)
The world is becoming more and more urban. Today, more than half of the world’s population lives in cities, compared with 10 percent in 1900. (16) Countries where most of the population is rural are seeing urbanization progress at staggering rates (1): In China, for example, more than a billion people will be living in urban centers by 2050, nearly double the number today. (20)
Read more: how urban environments contribute to obesity in low- and middle-income countries
Urban food and built environments, as well as the new technologies that accompany city living, can lead to poorer diets and more sedentary lifestyles. Urbanization does make it easier for people to receive health care and education, both of which can help curb obesity rates. (1) But in many low- and middle- income countries, new urban areas develop so quickly that the health care and education infrastructure is simply not in place.
Urban neighborhoods may also be less safe—or may be perceived as being less safe—than traditional village settings. Some (but not all) research suggests that when people perceive their neighborhoods to be less safe, they may be less likely to walk or do other physical activities outdoors; most of this research has been conducted in higher income countries, however, and more research is needed in low- and middle-income countries to see whether safety concerns there have a similar activity-limiting effect. (21,22)
Economic growth and urbanization lead to predictable shifts in diet, called “nutrition transitions.” In hunter-gatherer societies, people forage for food. Next, they shift to rudimentary agriculture, often enduring famine. As wealth and technology grow and famine recedes, calorie intake rises, leading to overeating and obesity. (3,5) Globalization has helped move many countries from famine to food sufficiency. But in many low- and middle-income countries, globalization has also accelerated the shift from food sufficiency to Western-style feast—and in turn, to obesity and obesity-related diseases.
Read more: the five patterns of the nutrition transition
China offers a good example of the rapid diet changes that accompany modernization, wealth, and the growing availability of low-priced, high-calorie foods:
- Cheap calories. As vegetable oil prices have dropped, average daily consumption in China has increased from about 1 tablespoon per person in 1989 to about 2.5 tablespoons in 2004—that amounts to an extra 183 calories per day. (7)
- Animal foods. Between 1989 and 1997, average daily intake of animal-source foods in China more than tripled; (23) Chinese adults, on average, eat more than 1,300 calories each day of animal products, including pork, poultry, beef, mutton, fish, eggs, and dairy. (5) Since high intakes of red meat are linked with an increased risk of heart disease, diabetes, and colon cancer, (24–26) the public health concern extends well beyond the extra calories
- Refined grains. White rice has been a traditional staple in China for thousands of years. Eating a diet rich in refined grains such as white rice can contribute to obesity, especially in people who are not active. (27) By 2004, 66 percent of China’s population worked in jobs that required only “very light activity,” up from 44 percent in 1989. (7)
- Sugary drinks. A recent survey of 4,600 Chinese adults in Hong Kong found that about 20 percent of men and 10 percent of women consume at least two servings of sugared beverages per day. (28) From 2006 to 2007, Coca Cola’s beverage sales in China shot up 18 percent, (29) and Coca Cola reportedly expects China to become its largest market by 2020. (30)
- Fast food. Fast food restaurants, a ready source of sugared beverages and high-calorie meals, are also on the rise. (31) McDonald’s, for example, opened its first restaurant in China in 1990; by 2006, it had 1,000 outlets in the country and, according to news reports, the company plans to double that number by 2013. (32,33)
Labor-saving devices have curbed physical activity in many facets of people’s lives, resulting in society-wide declines in individual energy expenditure that further accelerate obesity’s rise. Specific changes include the following:
Work. Many low- and middle-income countries have seen their workforces shift away from highly active jobs, such as farming and mining, to less active jobs in the manufacturing and service industries. (34) Even in traditional jobs, such as farming, people expend less energy than they did decades ago, due to mechanized farm equipment.
- Leisure. With the growth of mass media and computer technology, people are spending more of their time sitting indoors watching television and surfing the web, and less time in active outdoor play. (3) In south Korea, for example, TV viewing time rose 72 percent from 1983 to 2001. (35)
- Transportation. Walking and bicycling have frequently given way to cars and mopeds. In China, for example, new car sales have risen an estimated 30 percent a year in recent years. (36)
- Household chores. Increasing access to microwaves, washing machines, vacuum cleaners, and other labor-saving devices has begun to cut down on the human energy needed for household work in many countries. (3)
Rapid shifts to urban lifestyles and economic growth have also brought about behavior changes that may be contributing to the obesity epidemic in low- and middle-income countries:
- Shifting consumer preferences. Heavy food and beverage advertising on television and other mass media, as well as depictions of the West’s overeating culture, can directly influence food choices and reshape cultural norms around food, luring people toward the unhealthier options that originated in richer countries. (13) Children are especially vulnerable to advertising’s sway, and food advertising on television is no exception: Studies have found that advertising strongly influences children’s food preferences, as well as what children ask their parents to buy, and what they eat (37).
- Sleep deprivation. People who get less sleep tend to weigh more than those who get a good night’s sleep (38), and researchers have observed this trend not only in high-income countries but also in low- and middle-income countries such as Senegal, Tunisia, Brazil, and Taiwan. (39) Researchers speculate that the noise pollution, artificial lighting, and night life of urban environments may contribute to sleep deprivation.
- Stress. Psychosocial stress, a risk factor for obesity in Western countries, (40) may also contribute to obesity in low- and middle-income countries, though more research is needed. It’s possible that when people migrate to new urban areas, they could face more stress, since they are leaving behind traditional village social support, earning very poor wages, or struggling to find work.
- Women entering the formal-sector workforce. As women take jobs outside the home, they breastfeed less and their families consume more commercially-prepared foods. In high–income countries, these nutrition shifts have been associated with increased risk of obesity in children. (41–44) More research is needed in low- and middle-income countries to see if these worrisome trends play out as more women enter the formal workforce.
- “Little emperor syndrome.” Researchers hypothesize that China’s “one child policy” may contribute to childhood obesity. Parents with greater purchasing power are tempted to give their “little emperors” the televisions, computers, and other treats that they themselves never had growing up (45), inadvertently adding to child health risks.
There’s no question that globalization has improved the quality of life for many people in the developing world. But it has also increased access to cheap, unhealthy foods and brought with it more sedentary, urban lifestyles. From a public health perspective, the combination of these changes is creating a “perfect storm”—a catastrophic and costly rise in obesity and obesity-related diseases in countries that, at the same time, are still struggling with malnutrition and high rates of infectious diseases.
Obesity has already begun taking a toll on low- and middle-income countries. It’s not too late, though, to avert the full brunt of the storm, especially if low- and middle-income countries can learn from the mistakes of higher income countries, which did not recognize the health consequences of modernization until they were already taking a greater toll. Governments must implement policies that help individuals make better choices: for example, policies that support healthy eating, such as junk-food taxes and produce subsidies, and that encourage active living, such as school physical education requirements and urban bike lanes. If they do not, obesity promises to take a devastating toll on these emerging economies—and, given our global interconnectedness, on the world.
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The aim of the Harvard School of Public Health Obesity Prevention Source Web site is to provide timely information about obesity’s global causes, consequences, prevention, and control, for the public, health and public health practitioners, business and community leaders, and policymakers. The contents of this Web site are not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this Web site. The Web site’s obesity prevention policy recommendations are based primarily on a review of U.S. expert guidance, unless otherwise indicated; in other countries, different policy approaches may be needed to achieve improvements in food and physical activity environments, so that healthy choices are easy choices, for all.