A new study from America's Health Rankings predicts 103 million American adults (43 percent) will be obese by 2018, if obesity levels continue to grow at their current rate. At that point, the U.S. will spend approximately $344 billion dollars annually on health care costs attributable to obesity, according to the new study.

The study, conducted by Emory University professor Kenneth Thorpe, utilizes weight data, Census statistics and medical expenditure information, according to USA Today. Thorpe's study, The Future Costs of Obesity: National and State Estimates of the Impact of Obesity on Direct Health Care Expenses, is the first to provide projections for the future medical costs of obesity, and also provides state by state calculations for obesity levels and cost, according to a press release from the United Health Foundation. (Mississippi tops the list for the most obese population, while Colorado is all the way at the bottom.) USA Today has some highlights from the report:

• 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, then excess weight will cost the nation about $198 billion by 2018. (In comparison to the projection, that's a savings of about $820 per adult, according to the study.)
• If the obesity rate continues to rise until 2018, then Colorado may be the only state with less than 30 percent of residents who are obese.
• More than 50 percent of the population in several states could be obese by 2018: Oklahoma, Mississippi, Maryland, Kentucky, Ohio and South Dakota.

Rising levels of obesity are a troubling but all too familiar trend. According to a study published in Health Affairs earlier this year, the medical costs of obesity in the U.S. were about $147 billion in 2008 -- up from approximately $78.5 billion in 1998. Right now, 27 percent of the U.S. population is obese, an increase of 15 percent from 1989, according to Thorpe's study. Obesity is a serious risk factor for other chronic diseases, such as cardiovascular disease, diabetes and cancer. Chronic diseases make up a bulk of health care spending in the United States -- 75 percent of the approximately $2.2 trillion we spend on health care each year.

How can we fight the obesity epidemic? In his new book, Dr. David Kessler offers an insightful look into how and why Americans are hardwired to eat too much of the wrong foods. Part of fighting the obesity epidemic will be a cultural change and a rethinking of how we view food. Another step forward will be finding the right incentives to promote healthier lifestyles. The UK, for example, instituted public programs to make it easier for people to access swimming pools and bicycles. Last year, Alabama (number two on the list of the most obese states) started charging overweight or obese state employees a $25 monthly fee for their health insurance, a strategy they had already implement for smokers. In contrast, Arkansas, Missouri, and Ohio offer discounts and positive financial incentives to healthy employees, rather than extra fees. There's no easy answer to reversing the obesity epidemic in the U.S. -- but we do know it is a problem we can't afford to ignore. Realigning incentives and rethinking our habits are two important steps forward.