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.
