Childhood obesity is a real problem in America—just ask Michelle Obama—and for years has been the focus of many well intentioned government initiatives. Could they be making a difference? Although officials don't really know why, and the numbers are still very early, it seems that several American cities—including NYC—are reporting declines in obese children. Surprise!

"It’s been nothing but bad news for 30 years, so the fact that we have any good news is a big story," Thomas Farley, head of the Department of Health, told the Times. In NYC the DOH saw a 5.5 percent decline in the number of obese schoolchildren from 2007 to 2011. But it isn't just us! Other cities have also seen dips in the number of overweight students including Philadelphia (5 percent) and LA (3 percent).

But the reason for the declines remains a mystery for the moment:

Researchers say they are not sure what is behind the declines. They may be an early sign of a national shift that is visible only in cities that routinely measure the height and weight of schoolchildren. The decline in Los Angeles, for instance, was for fifth, seventh and ninth graders — the grades that are measured each year — between 2005 and 2010. Nor is it clear whether the drops have more to do with fewer obese children entering school or currently enrolled children losing weight. But researchers note that declines occurred in cities that have had obesity reduction policies in place for a number of years.

So it could be because of anti-obesity programs or it could just be that the fat kids aren't even bothering to go to school anymore. Only time will tell. In the meantime, cities and health groups are continuing with their fat trimming programs. After all, according to the CDC 17 percent of those under 20 in America are obese. And all that fat in a few years really starts to weigh down on the government's wallet.