One of America’s enduring health problems is childhood obesity, which has been on the rise for decades. But now there are rays of hope around the country that the process may be turning around. In major metropolitan areas including New York and Los Angeles, and in smaller cities around the country, childhood obesity is declining for the first time in 30 years. The drops are small, but they're raising hopes that obesity rates may have finally reached a peak. Sabrina Tavernise is a reporter for the New York Times.