Much of that could be explained by the severely obese, those 80 pounds or more overweight, whose numbers are expected to more than double and who face much more severe threats to their health.
In the American Journal of Preventive Medicine study, researchers predict that the rate of adult obesity will climb from the current 34 percent to 42 percent by 2030, or to an additional 32 million people.
After skyrocketing rates in the 1980s and ’90s, that rate of increase might have slowed or appears to be plateauing, said lead author Dr. Eric Finkelstein, an associate research professor in the Duke Global Health Institute.
“Clearly, the rise is increasing at a decreasing rate,” he said, except among the severely obese (defined as those with a body mass index of 40 or greater), who are expected to more than double from 5 percent now to 11 percent in 2030.
That group has a significantly higher risk of chronic illnesses such as diabetes and heart disease, Finkelstein said.
“They’re also much more expensive,” he said.
The researchers used a model that looked at several variables that influence obesity, such as Internet access, the price of healthful vs. unhealthful foods and the number of fast-food and other restaurants per 10,000 people, all of which can increase obesity, Finkelstein said.
The rates are expected to be worse among blacks and Hispanics. Among the severely obese, society has changed in such a way that it allows them to sustain and increase severe weight gain, Finkelstein said.
The study looked only at adults, but the childhood obesity crisis could be a factor in the future, said Dr. William Dietz, the director of the Centers for Disease Control and Prevention’s Division of Nutrition, Physical Activity and Obesity, which also took part in the study.
Among the severely obese in one population study, about 50 percent were obese as children or adolescents, he said.