The Weighting Game
Youfa Wang has witnessed obesity’s global surge firsthand. As a boy in China in the 1970s, access to food was the problem. Now, when he returns home, he is astonished at the number of obese kids as well as the McDonald’s ads in apartment elevators. To get ahead of worldwide obesity (which has doubled since 1980) and to stem burgeoning rates of diabetes, hypertension and heart disease, Wang founded the Johns Hopkins Global Center on Childhood Obesity with a $16 million-plus NIH grant. A fast-talker with a computeresque command of complex data, Wang, MD, PhD, recently led Johns Hopkins Public Health editor Brian W. Simpson on a brisk tour of the global child obesity epidemic and the Center’s quest for solutions.
Eat less and exercise more are pretty simple messages. Why can’t we fix the child obesity epidemic?
That’s a good question, but a very tough one. Studies show about 70 percent of variation in obesity is due to genetics. But over the past two to three decades in the United States and many other countries, prevalence has been increasing even though people’s genes have not changed. We published a study in 2006 based on data from over 60 countries. Almost all of them saw an increase in obesity among children. That clearly suggests the environmental, behavioral triggers rather than genetics, though some will argue the gene-environment interactions are the determinant of obesity.
What concerns you most about the global child obesity epidemic?
The scope and its serious health and financial consequences. For a big country like the U.S., already one-third of the children’s population is overweight or obese. In China, the rate in the major cities is already 30 percent, though it was less than 3 percent in 1985. There are so many other countries that suffer from such a high prevalence and also an increasing rate.
If you can prevent a child from becoming obese, are you preventing her from becoming an obese adult?
Yes. In general, one-third to two-thirds of overweight children will remain overweight when they become adults. I should also say, though, that many obese adults were not obese when they were children.
Is each country’s obesity epidemic unique?
Yes, each country has its unique challenges, but we also see some common patterns. In developed countries, we know that people with higher income, better education are less likely to be overweight or obese. But in most developing countries, it’s the opposite: People who are richer have better access to energy-dense food, processed food and can afford to have more sedentary lifestyles. They are more likely to be overweight and obese. We also see considerable differences between gender, age and ethnic groups within countries.
Can you compare China’s developing obesity epidemic to the U.S. epidemic?
In the United States, [it began in] the early ’80s. Since the mid-2000s, the data suggest a plateau. In China, the rapid increase started [in] the early 1990s. The rate of increase in China has been much faster than in the United States—about double—due to China’s remarkable economic development and social-environmental changes, which have profound impacts on people’s lifestyles and health.
Are there countries that have both rapidly developed and escaped this problem?
No, but some countries have relatively low obesity rates. South Korea is an example, though obesity has become a public health threat in recent years. The other model country is Japan, which has the best longevity worldwide.
What’s their secret?
One thing is traditional culture. Compared with China, they did a much better job preserving their traditions, including their traditional diet. In Japan, they do not use so much cooking oil or sugar, and their portion size is very small. The second part is culture. I think in the United States in general people value individualism. They value today, and they value the joy of life. But some Asian societies, influenced by Buddhism and other religions and culture values, not only look at current life but also future life and the larger population. They take a longer view. When you think about future generations, you have to control yourself.
How is your Center different from others?
This is the only global center of child obesity in the world. We have researchers from epidemiology, nutrition, health policy, health economics and other disciplines. We have over 50 investigators from 15 other institutions including the NIH and institutions from other countries. Our Center will also provide grants and training scholarships to researchers worldwide to study the impact of policy or environmental changes on child obesity. We want to train the new generation of researchers, public health professionals and policymakers.
Tell us about some of the Center’s projects.
Our Center has four key research projects and will support about 20 to 25 small-scale studies in the next five years to study the environmental, policy drivers of the obesity epidemic and find sustainable solutions. In a local study, we will [examine] the interaction between genetics and the environmental factors for the risk of obesity. Another key project is a Baltimore-based intervention study of modifying the food system.
This epidemic is global and entrenched. How could you have an effect?
It may be difficult to measure the effect this Center will bring in the next two years to five years, but we feel confident there will be several indicators people can see [after that]. One example is how many research programs our Center will be supporting in different countries, which then will result in potential policy programs. That’s what we really hope is the effect of this Center. We really hope the kind of people our Center trains—people who have systems thinking—will influence the obesity prevention effort in multiple countries.
What made you dedicate your career to childhood obesity?
I feel children, especially young children, are very vulnerable. They need care. They need support. There should be adults around them who can make a big difference in their lives. I want to become one of those adults, not only for my own children but for other children, even worldwide.