A new study predicts roughly half of the U.S. population will be obese within a decade.

By 2030 nearly 1 in 2 adults, or 48.9%, will have obesity, and the prevalence will be higher than 50% in 29 states and not below 35% in any state, according to the study published in the New England Journal of Medicine.

It also predicted that severe obesity is likely to become more prevalent among women, non-Hispanic black adults and low-income adults.

Leant author Zachary Ward, an analyst at Harvard Chan School's Center for Health Decision Science, told CNN severe obesity is rising in the country.

"It's really hard to lose weight," Ward said. "It's really hard to treat obesity. So prevention really has to be at the forefront of efforts to combat this growing epidemic."

Aviva Must, chair of Tufts University's Public Health and Community Medicine, said obesity was rare 50 years ago. "People who were poor were underweight, not overweight. But that has changed," she said.

Increased sugar-sweetened beverages and ultra-processed foods, among other factors, are blamed for severe obesity,.

Must, an expert who was involved in the study, told CNN that low food prices are "certainly part" of the projected situation as well as limited options for physical activity.

"And there's a lot being written about the stress of structural racism and how that influences people's behavioral patterns. So it's very complicated," said Must.

The prevalence of adult obesity and severe obesity will continue to increase nationwide, with large disparities across states and demographic subgroups, the study concluded.

It used body-mass index (BMI) data reported by more than 6 million adults. Currently, 18% of the U.S. population is severely obese.