The stunning three-decade rise in childhood obesity that prompted the government to declare an "epidemic" of fat appears to have leveled off, although the obesity rate is still more than three times higher than in the 1970s, researchers reported today.
The analysis, published in today's Journal of the American Medical Association, was based on data from tens of thousands of children showing that the percentage of obese youngsters has been roughly stable since 1999 in every age and racial group.
The level of obesity "is still too high," said lead author Cynthia Ogden, an epidemiologist with the federal Centers for Disease Control and Prevention. But she added: "Maybe there is some cause for optimism." The mystery is what caused the plateau.
The leading possibility is that educational and regulatory campaigns to get children to eat less junk food and exercise more have begun to pay off.
The findings "may signal that this national epidemic is not an unstoppable force," said Dr. Risa Lavizzo-Mourey, president of the Robert Wood Johnson Foundation, which has committed $500 million to promoting physical activity in communities and improving nutrition in schools.
"When parents, government, schools, the food and beverage industries, other businesses and the nonprofit and philanthropic sectors work together, we can make progress, and we can reverse this epidemic," she said in a statement.
Some researchers, however, said the answer could be that the epidemic has simply reached a saturation point - kids just can't get any fatter.
"Eventually it had to level off," said S. Jay Olshansky, an epidemiologist at the University of Illinois at Chicago who was not involved in the study. "The question was when. Maybe this is it."
The rise in obesity among children and adults has been one of the biggest public health issues of the past few years, in this country and around the world.
It was first noticed by researchers in the 1980s as a relentless upward slope that threatened to undo progress on heart disease and worsen other killer illnesses influenced by weight, including diabetes, high blood pressure and some types of cancer.
The CDC issued an unsettling report in 2004 that concluded obesity caused 400,000 deaths a year in the United States, just slightly below the death toll from smoking.
About a third of U.S. adults are obese, based on a measurement known as body mass index, a ratio of height and weight.
Of particular concern has been obesity in children because their eating patterns set them on course for lifelong health problems.
One study in 2005 found that as a result of obesity, children today could be the first generation of the modern era to live shorter lives than their parents.
The latest study showed that 16.3 percent of children ages 2 to 19 are obese and an additional 15.6 percent are overweight.
The government has been tracking the heights and weights of children since the 1970s as part of a long-term health and nutrition survey. By today's definitions, 5 percent of children at that time were obese and 10 percent were overweight.
The latest analysis looked at 4,207 children surveyed in 2005 and 2006.
When the researchers incorporated the new numbers into their analysis, their statistical model showed that 1999 marked the start of the leveling-off. A study last year showed obesity rates among adults stabilizing.
Alan Zarembo writes for the Los Angeles Times.