More Americans Getting Thicker Around the Middle

America's waistlines have been expanding rapidly in the last decade, according to the Centers for Disease Control and Prevention.

Fifty-four percent of U.S. adults have abdominal obesity, which is a waistline of 35 inches or more.

Researchers found that from 1999 to 2012 the average American male waistline grew by an inch to 40 inches. The average waist size for women grew two inches to 38 inches.

People whose fat has settled mostly around their waistline instead of other places run a higher risk of heart disease, diabetes, and other issues related to obesity.

"The increase is a concern. There's no question about that," Dr. William Dietz, an obesity expert formerly with the CDC who was not involved in the study, said.

"What it suggests is that even though the obesity rate may be stable, fat distribution may be changing, which would mean that we shouldn't be complacent about the plateau," Dietz added.