One in three American adults is obese, a national level that has stayed the same in recent years, said US data released on Tuesday.

About one in six children and teenagers are also obese, according to the Journal of the American Medical Association report which showed that obesity remains a significant problem in US society despite efforts to combat it.

"Obesity prevalence shows little change over the past 12 years, although the data are consistent with the possibility of slight increases," said the article.

Obesity is defined as a body mass index, or a formula based on height and weight, that is 30 or higher.

Examples would include a six-foot tall man weighing more than 222 pounds (1.82 meters and 100 kilograms) or a five-foot-seven-inch tall woman weighing 192 pounds (1.70 meters and 87 kilograms).

According to the JAMA report, 35.7 percent of US adults are obese and so are 16.9 percent of children and teenagers age two to 19.

When overweight people are added to the adult tally, the prevalence of overweight and obese people jumps to 68.8 percent of the US population.

"The good news from the report is that rate of obesity in US adults from 2003-2008 and 2009-2010 has not increased significantly," said Nancy Copperman, director of public health at North Shore-Long Island Jewish Health System in New York.

"This is a change from previous reports where obesity rates continued to rise. Public health efforts to address obesity may be having a positive effect," added Copperman, who was not involved in the JAMA study.

However, more needs to be done to target such efforts in minority groups who tend to have higher rates of obesity than whites, she said.

For instance, obesity rates among white men were 36.2 percent in 2009-2010 compared to 38.8 percent among black men.

The obesity prevalence in white women was 32.2 percent compared to 58.5 percent in black women.

The data came from the National Health and Nutrition Examination Survey which included measured height and weight for about 6,000 adult men and women and 4,000 children and teens in 2009-2010.