About 41 percent of Americans will be obese and 11 percent will be severely obese by 2030, researchers from the U.S. Centers for Disease Control and Prevention and Duke University warn on Monday.

About 26 percent of adults in the U.S. were obese in 2010, weighing over 30 pounds above the healthy limit, and 6 percent were severely obese, weighing 100 pounds or more over a healthy weight, and the latest estimates on the U.S. obesity epidemic are worrying health experts who predict a dramatic jump in health care costs if the rise in obesity rates continues on its current path.

The findings suggest that 32 million more people would become obese within the next two decades, which would result in substantially greater medical expenditures and rates of absenteeism, costing the country billions of dollars.

Lead author Dr. Eric Finkelstein, an associate research professor in the Duke Global Health Institute, said that controlling the obesity rates to keep it from increasing even more could save the country nearly $550 billion in medical bills over the next 20 years, according to a news release.

Finkelstein and his team based their calculations on self-reported weight and height from people participating in CDC’s Behavioral Risk Factor Surveillance System and state-level data from the Bureau of Labor Statistics and other organizations.

Researchers calculated obesity by using the body mass index (BMI), people with a BMI of over 30 are considered obese, and while researchers previously estimated that by 2030, 51 percent of Americans would be obese, the latest estimates took into account other factors and determined that the past predictions were too high.

While severe obesity, having a BMI of 40 or more, was once rare, it now affects 1 in 20 Americans is estimated to double in 2030. Obesity kills roughly 400,000 people in the United States alone, and is becoming increasingly prevalent both domestically and internationally. Severely obese people have the highest risk of developing diabetes, heart disease and other conditions caused by excess weight.

"Should these forecasts prove accurate, the adverse health and cost consequences of obesity are likely to continue to escalate without a significant intervention," co-author Justin Trogdon said in a statement.

"People need to make healthy choices, but the healthy choices must first be available and accessible in order to make them," Dietz added. "In the coming days at our Weight of the Nation conference, CDC and its partners will emphasize the proven, effective strategies and solutions that must continue to be applied to help make the healthy choice the easy choice."

Researchers reported their findings on Monday at the CDC's Weight of the Nation conference in Washington, D.C., and the study is also published in the May 7 issue of American Journal of Preventive Medicine.