A person with a body mass index (BMI) of 30 or greater is considered obese. BMI is calculated as weight in pounds divided by height in inches squared and multiplied by 703.

If America's obesity epidemic continues unthwarted, obesity rates could reach 44 percent in all states by 2030, according to a new report.

Obesity rates could reach or exceed 60 percent in 13 states, 10 of them in the South, the report adds. Mississippi is expected to have the highest obesity rate in 2030, at 66.7 percent.

Currently, Colorado has the lowest obesity rate, at 20.7 percent, and Mississippi has the highest, at 34.9 percent, according to the report, co-written by the Robert Wood Johnson Foundation's Health Group and the Trust for America’s Health.

Twenty years ago, no state had an obesity rate above 15 percent, the report says.

The continued rise in obesity rates also could lead over the next two decades to more than 6 million new cases of Type 2 diabetes, 5 million new cases of coronary heart disease and 400,000 new cases of cancer, the report says.

The cost of treating obesity-related disease could increase at least $48 billion and as much as $66 billion per year, the report says.

However, if each state reduced its residents' average body mass index (BMI) by 5 percent, thousands of obesity-related health problems could be avoided, and no state would have an obesity rate above 60 percent by 2030, the report says. For the average adult, a 1 percent decrease in BMI is about 2.2 pounds.

"We really are looking at two futures for American's health," said Michelle Larkin, assistant vice president for the Robert Wood Johnson Foundation's Health Group. The country needs to invest in obesity prevention "in a way that matches the financial toll the epidemic takes on the nation," Larkin said.

The study used information from a yearly nationwide telephone survey called the Behavioral Risk Factor Surveillance System, and the researchers created a model to predict obesity rates under different scenarios.

If nothing about the current trends changes, 39 states could have obesity rates above 50 percent by 2030, the report says. Besides Mississippi, states with the highest projected obesity rates are Oklahoma at 66.4 percent, Delaware at 64.7 percent, Tennessee at 63.4 percent and South Carolina at 62.9 percent.

Under the second scenario, in which each state lowers its BMI by 5 percent, the findings show that for every 100,000 people, states could avoid up to 3,200 cases of Type 2 diabetes, 2,500 cases of high blood pressure, 2,900 cases of coronary heart disease and stroke, 1,380 cases of arthritis and 277 cases of cancer.

In addition, almost all states would save between 6.5 percent and 8 percent on obesity-related health care costs. That would mean savings of $81.7 billion in California and $1.1 billion in Wyoming, the report says.

The report has several recommendations for reducing the severity of the obesity epidemic, including increasing physical activity in schools and making healthy foods such as fruits and vegetables more affordable.

"Policy changes can help make healthier choices easier for Americans in their daily lives," said Jeff Levi, executive director of the Trust for America’s Health.

Pass it on: America is on track to have a 44 percent obesity rate in each state in 2030.

This story was provided by MyHealthNewsDaily, a sister site to LiveScience. Follow Rachael Rettner on Twitter @RachaelRettner, or MyHealthNewsDaily @MyHealth_MHND. We're also on Facebook & Google+.