Their study, published in the International Journal of Obesity, found one-third of the world's population is already considered overweight or obese.

The researchers at Tulane University School of Public Health and Tropical Medicine said the findings are based on peer-reviewed data from 1990 to 2007 from more than 100 countries. Overall, the researchers used 72 national, 22 multi-site and 14 regional studies from 106 countries, covering approximately 88 percent of the world's population.

The study finds that as of 2005, approximately 23.2 percent of the world's adult population was overweight and 9.8 percent was obese. Roughly 937 million adults were overweight and 396 million were obese. If those trends continue, the number of overweight individuals will more than double to 2.16 billion by 2030 and the number of obese adults will grow to 1.12 billion during the same time period.

"Epidemiologic studies indicate that overweight and obesity are important risk factors for diabetes, cardiovascular disease, cancer and premature death," study authors say in a statement. "The high prevalence of overweight and obesity, combined with their concomitant health risks makes it a worldwide public health challenge."