The number of American men and women with big-bellied, apple-shaped figures—the most dangerous kind of obesity—has climbed at a startling rate over the past decade, according to a government study. People whose fat has settled mostly around their waistlines instead of in their hips, thighs, buttocks, or all over are known to run a higher risk of heart disease, diabetes, and other obesity-related ailments. The study says 54% of US adults have abdominal obesity, up from 46% in 1999-2000, researchers reported in the Journal of the American Medical Association. Abdominal obesity is defined as a waistline of more than 35 inches in women and more than 40 inches in men.
During the 12-year period studied, the average waist size in the US expanded to 38 inches for women, a gain of 2 inches. It grew to 40 inches for men, a 1-inch increase. The expansion in waistlines came even as the overall level of obesity—as defined not by waist size but by body mass index, or BMI—held fairly steady. "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," says Dr. William Dietz, an obesity expert formerly with the Centers for Disease Control and Prevention, now at George Washington University. (Read more obesity stories.)