This increase is responsible for 89 percent of the increase in obesity costs that occurred during this time period. The results reveal that obesity is now responsible for 9.1 percent of annual medical expenditures, compared with 6.5 percent in 1998.

The results also showed that an obese person has $1,429 per year more medical costs, or about 42 percent more costs, than someone of normal weight. Costs for an obese Medicare recipient are even greater.

Much of the costs from obesity to Medicare are a result of the added prescription drug benefit and not from surgical treatments for obesity.

"Although bariatric surgery and other obesity treatments are increasing in popularity, in actuality these treatments remain rare," said Eric Finkelstein, Ph.D., director of RTI's Public Health Economics Program and the study's lead author. "As a result, the medical costs attributable to obesity are almost entirely a result of costs generated from treating the diseases that obesity promotes (such as high blood pressure, diabetes, heart disease, stroke and many other serious health problems). Thus, obesity will continue to impose a significant burden on the health care system as long as the prevalence of obesity remains high."

Medicare prescription drug payments for obese individuals are roughly $600 more per year than drug payments for normal weight beneficiaries. The researchers also found that 8.5 percent of Medicare expenditures, 11.8 percent of Medicaid expenditures, and 12.9 percent of private payer expenditures are attributable to obesity.