"Physical activity has all but disappeared out of most people's lives, unless they make it a separate task," Farley added. "At the same time, and even more importantly, food has increasingly become cheap, ready to eat, available everywhere, and so people have adopted habits to snack constantly."

Farley says the New York childhood obesity rate is still at 20 percent. But New York's decline goes against a rising national trend. And the health commissioner is heartened that the rate has fallen at all for the first time in decades - 10 percent among five and six year olds - which gives him reason to believe some youngsters will adopt lifelong habits of healthy eating.