U.S. obesity rates have been increasing for several decades, but the latest jump caught even experts by surprise: rising from 33.7 percent of adults in 2007-08 to 39.6 percent in 2015-16 (the latest data), according to CDC researchers, writing in the Journal of the American Medical Association in April 2018.
Severe obesity rose from 5.7 percent to 7.7 percent of adults. That means there are about one-fifth more Americans in these categories than just a decade ago.
The rapid increase in obesity has occurred in men and women and in every age group except children and teenagers, whose rate rose only modestly.
Weight categories are determined by body mass index (BMI), a formula involving weight and height: overweight is 25 to 30; obesity, 30 or more; severe obesity, 40 or more. Someone 5'10" is obese starting at 209 pounds; severely obese, 279 pounds and above.