Are Vegetables and Exercise Causing Childhood Obesity in China?

New research shows that behaviors that promote wellness in America might be part of unhealthy lifestyles abroad

Healthcare professionals usually endorse a balanced diet plus regular exercise as the formula for fitness. Surprising new research from the University of Southern California's Keck School of Medicine, however, suggests this may not hold true in China, where such healthy habits coexist with a sharp increase in the country's number of overweight and obese children.

"I hadn't seen any data ever—and I've seen lots of data—to show that eating fruits and vegetables, for example, is related to higher weight," says Donna Spruijt-Metz, a coauthor of the study and an expert in pediatric obesity.

For the study, published in the current issue of The American Journal of Health Behavior, Spruijt-Metz and her fellow researchers analyzed cross-sectional survey data on food-intake frequency from 9,023 middle and high school students and one parent from seven large cities in China. They found that sedentary activities, such as watching TV or using the computer, were related to greater odds of being overweight, just as in the U.S. More interestingly, they also uncovered several unexpected behaviors that were correlated with higher incidences of being overweight, including more vigorous exercise, less candy and fast food intake, less frequent snacking, more fruit consumption, and higher parental educational attainment.

In their analysis, the researchers—some of whom are sociologists and psychologists from East Asia—flesh out these factors, and point to cultural and methodological reasons to account for these obesity-related paradoxes. Diets rich in vegetables, the researchers suspect, may also be rich in oil as the two most common methods of preparing vegetables is deep-frying and stir-frying. More educated parents, who are likely also richer, may be able to afford fast food, which is cheap in America but not so much in developing countries. Also, overweight children may be underreporting their intake of unhealthy food and may misperceive the quality of the exercise they do.

"Maybe it's just overall a larger energy intake," Spruijt-Metz adds. "There's still a cultural perception in China that it's healthy and desirable if you're beefier."

Understanding the obesity epidemic among Chinese children is more critical than ever. Recent data from Johns Hopkins shows that about 20 percent of Chinese kids and over a third of the boys are overweight or obese. A 2004 report from Peking University places the number of overweight kids at less than 2 percent back in 1985.

In general, the surge in obesity is thought to be related to the country's rapid development and Westernization. As Johns Hopkins international health professor Youfa Wang puts it, "The dramatic changes in social and environmental factors, and the individual and family's lifestyles, including Westernized eating behaviors, are the key drivers of childhood obesity in China."

Spruijt-Metz notes that the epidemic is similar to what has happened in America, with one noticeable difference. "What strikes me most about obesity in China is that it's like watching the U.S. except in high speed," she says. "It took Americans many decades to get this fat, and it took them no time at all."

Still, one thing is clear from the research: Western determinants of and solutions for obesity might not always apply to China.

Image: Sheng Li/Reuters