Dr. Robert Zarr, second from right, leads a hike through a park in Washington, D.C. Diana Bowen/National Park Service hide caption

itoggle caption Diana Bowen/National Park Service

The CDC would be happy with these guys, who were playing in Birmingham, Ala., in July 2013. Teenage boys say basketball is their favorite activity. Mark Almond/AL.COM /Landov hide caption

itoggle caption Mark Almond/AL.COM /Landov

Playing outside can help kids — and their parents — maintain a healthy weight. iStockphoto hide caption

itoggle caption iStockphoto

Students at Lowell High School in Michigan sit down for lunch. Shorter lunch breaks mean that many kids don't get enough time to eat and socialize. Emily Zoladz/Landov hide caption

itoggle caption Emily Zoladz/Landov

Just knowing that someone is obese doesn't mean they would benefit from bariatric surgery, doctors say. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Teenagers put in more than two hours a day of TV time on average, still more than what pediatricians say is healthy. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Small declines in obesity among young kids could help stem bigger problems in the future. Ocean/Corbis hide caption

itoggle caption Ocean/Corbis

Napping in class may be common, but it's also a sign that kids need more sleep. iStockphoto.com hide caption

itoggle caption iStockphoto.com

A poll needs to ask about randomly selected children in households across the country to bring context to what's happening with kids like 7-year-old Henry Condes in Los Angeles. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

A new poll explores what happens in American households during the hours between school and bedtime. Image courtesy of The Bishop family (left), The Benavides family (top right), NPR (center) and The Jacobs family (bottom right) hide caption

itoggle caption Image courtesy of The Bishop family (left), The Benavides family (top right), NPR (center) and The Jacobs family (bottom right)