Researchers predict nearly half of Americans will be obese by 2035. What to know.

Adult obesity in the United States has gone up over the past 30 years and more increases are expected in the next decade, according to a new study.

In the study, published Tuesday, Jan. 28, in JAMA, researchers found 19.3% of U.S. adults were living with obesity in 1990, which increased to 42.5% by 2022. The researchers also forecast the number will increase to 46.9% by 2035.

Using two cross-sectional, nationally representative surveys, the study analyzed data from a total of 11,315,421 U.S. participants.

Registered dietitian Ashley Koff, who was not involved in the study, told USA TODAY it's not surprising to see that these numbers have increased for a multitude of factors.

But she also said the way the study defined obesity using BMI, a measurement based on height and weight, is problematic. Other health experts have also criticized the method as outdated.