Weighing in on child obesity

Youfa Wang, an associate professor at the Bloomberg School of Public Health, is the director of the Johns Hopkins Global Center on Childhood Obesity. He sat down for a Q&A with Johns Hopkins Public Health magazine editor Brian W. Simpson to talk about the childhood obesity epidemic and what the center is doing about it.

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.