The majority of U.S. adults are projected to be overweight or obese by 2030, according to a study from Johns Hopkins Bloomberg School of Public Health, the Agency for Healthcare Research and Quality, and the University of Pennsylvania School of Medicine.

Recent figures from the Centers for Disease Control and Prevention show that about 62 percent of adults are overweight. With that percentage expected to grow by 23 percent over the next two decades, obesity-related health costs are expected rise to about $956.9 billion, according to the study, which was published in the July 2008 online issue of Obesity.

"National survey data show that the prevalence of overweight and obese adults in the U.S. has increased steadily over the past three decades," said Dr. Youfa Wang, the lead author of the study and associate professor with the Bloomberg School's Center for Human Nutrition. "If these trends continue, more than 86 percent of adults will be overweight or obese by 2030 with approximately 96 percent of non-Hispanic black women and 91 percent of Mexican-American men affected.

There are many ways to determine if a person is overweight, according to the National Institutes of Health, but many experts believe that a person's body mass index is the most accurate measurement of body fat.

If you're BMI is between 25 and 29.9 you are considered overweight. Adults with a BMI greater than 30 (about 30 pounds overweight) are considered obese, and anyone who is more than 100 pounds overweight is considered morbidly obese, the NIH said on its Web site.

Click to to calculate your BMI.

“This would result in 1 of every 6 health care dollars spent in total direct health care costs paying for overweight and obesity-related costs,” Wang said in a press release.

The researchers conducted their analysis on data collected over the past three decades from nationally representative surveys.

"The health care costs attributable to obesity and overweight are expected to more than double every decade," Wang said. "This would account for 15 to 17 percent of total health care costs spent. Due to the assumptions we made and the limitations of the available data, these figures are likely an underestimation of the true financial impact."

Researchers estimate that children and young adults may have a shorter life expectancy than their parents if the obesity epidemic is left unaddressed.

If current trends continue, researchers said the U.S. Department of Health and Human Services will not meet its Healthy People 2010 initiative to increase the proportion of adults who are at a healthy weight and to reduce the proportion of adults who are obese.

Click here for the study published in the journal Obesity.