Obesity rates could have hit a plateau, some scientists propose, if only a certain percentage of children are genetically predisposed to obesity, and that share has gotten fat already. Timothy Olds, a professor of health sciences at the University of South Australia, believes genetics could play a role, but he also points to "all the little things people are doing to encourage healthy weight."
Some researchers argue the data used to produce these conclusions are flawed. And other scientists say that while the methodology of the recent batch of studies appears sound, the findings aren't definitive. Future surveys using different methodologies, they say, could show obesity rates on the move again.
"Most developed countries are not doing annual surveys," says Tim Lobstein, director of policy and programs for the International Obesity Taskforce, a London-based research and advocacy group. "We probably know more about growth patterns in cattle than we do for human children."
In the U.S., obesity rates among children hovered at about 16% between 2002 and 2006, according to the U.S. Centers for Disease Control and Prevention. The leveling off was a surprise to William Dietz, director of the CDC's division of nutrition, physical activity and obesity, who notes that prominent anti-obesity-awareness campaigns have only been around for a few years. (A survey conducted by the National Opinion Research Center, a group based at the University of Chicago, showed increases in most states between 2003 and 2007, but that was based on phone interviews rather than physical examinations.)
Some health advocates have been leery of giving too much attention to the encouraging numbers, noting that a plateau or small decrease won't stave off the high financial and medical toll likely in store for today's overweight children.
"What I worry about is that people will read these numbers and think we've got this solved," says Dr. Dietz of the CDC. "I'm encouraged by the results, but this is no time for complacency."