If Americans continue to pack on pounds, obesity will cost the USA about $344 billion in medical-related expenses by 2018, eating up about 21% of health-care spending, says the first analysis to estimate the future medical costs of excess weight.

These calculations are based on the projection that in 10 years 43% of Americans adults may be obese, which is roughly 30 or more pounds over a healthy weight, if obesity continues to rise at the current rate. Extra weight increases the risk of diabetes, heart disease and many types of cancer.

This report comes as the country struggles to find ways to curb medical costs and Congress debates health care legislation.

“Obesity is going to be a leading driver in rising health-care costs,” says Kenneth Thorpe, chairman of the department of health policy and management at Emory University in Atlanta. Thorpe did this special analysis on obesity for America’s Health Rankings, the 20th annual assessment of the nation’s health on a state-by-state basis.

“There is a tsunami of chronic preventable disease about to be unleashed into our medical-care system which is increasingly unaffordable,” says Reed Tuckson of United Health Foundation, sponsor of the report with the American Public Health Association and Partnership for Prevention.

Using weight data, Census statistics and medical expenditure information, Thorpe found:

•An obese person will have an average of $8,315 in medical bills a year in 2018 compared with $5,855 for an adult at a healthy weight. That’s a difference of $2,460.

•If the percentage of obese adults doesn’t change but stays at the current rate of 34%, then excess weight will cost the nation about $198 billion by 2018.

•If the obesity rate continues to rise until 2018, then Colorado may be the only state with less than 30% of residents who are obese.

•More than 50% of the population in several states could be obese by 2018: Oklahoma, Mississippi, Maryland, Kentucky, Ohio and South Dakota.

The report adds to the growing body of evidence of obesity’s impact on medical costs. A study released in July showed that obese Americans cost the country about $147 billion in weight-related medical bills in 2008, double what it was a decade ago. It now accounts for about 9.1% of medical spending.

Overall, the United States spends about $1.8 trillion a year in medical costs associated with chronic diseases such as diabetes, heart disease and cancer, and all three are linked to smoking and obesity, the nation’s two largest risk factors, according to the America’s Health Rankings report.

Smoking is still the No. 1 preventable cause of death in the country, accounting for about 440,000 deaths annually, the report says.

About one in five Americans smoke. More than 3 million people quit smoking this past year. The percentage of people who smoke varies by state, from 9.3% in Utah to more than 25% in Kentucky, Indiana and West Virginia, the study says.

“This report is an urgent call to take much more aggressive action to deal with key disease risk factors such as obesity and smoking,” Tuckson says.

Health economist Eric Finkelstein, co-author of The Fattening of America, says medical costs won’t go down unless Americans make a serious effort “to slim down by improving their diet and exercise patterns.”  By Nanci Hellmich, USA TODAY