THURSDAY, May 23, 2019 (HealthDay News) -- Many people -- including those who are overweight themselves -- view people with obesity as less human or less evolved, new research reveals.

In four online studies questioning more than 1,500 participants from the United States, the United Kingdom and India, researchers also found that dehumanization of those with obesity predicted support for policies that discriminate against this group.

"We've obviously heard the way that people speak about people with obesity," said study author Inge Kersbergen. She's a research fellow at the University of Sheffield in England.

"In that sense, we'd be surprised if we didn't find anything," Kersbergen said. "But I don't think we were prepared for the magnitude of our findings."

In the first report believed to indicate that people with obesity are blatantly dehumanized, Kersbergen and her colleagues pooled data examining whether dehumanization depended on participants' body weight and if those with obesity were dehumanized more than other social groups different from the norm.

These other social groups included those based on appearance, such as underweight Americans, or illness, such as Americans with cancer.

Different measures of attitudes toward people with obesity were used in the four separate studies. For example, participants indicated how evolved they considered various groups of people to be, including Americans, obese Americans, Americans addicted to heroin, Arabs, homeless Americans, and employed Americans.

The research also included measures of subtle dehumanization of people with obesity, disgust toward obesity, beliefs about weight controllability, anti-fat prejudice and support for policies discriminating based on weight.

Nearly 40% of adults in the United States are obese, according to 2015-2016 statistics from the U.S. Centers for Disease Control and Prevention. Obesity is defined as a height-weight ratio known as body mass index (BMI) of 30 or higher, and markedly increases the risks for heart disease, stroke, diabetes and certain types of cancer, the CDC says.

While dehumanization was most pronounced among thinner participants, all groups rated an "obese American" as less evolved and less human than "Americans," except for participants who were extremely obese (with a BMI of 35 or higher).