Weight discrimination — unequal treatment or prejudice toward overweight or obese individuals — is as prevalent as racial discrimination, according to research published earlier this month by the Rudd Center for Food Policy and Obesity.

But despite its prevalence, weight discrimination continues to be socially acceptable and thus is not looked down on as severely as discrimination based on gender or race, said Rebecca Puhl, director of research at the Rudd Center and lead author of the study.

“These results show the need to treat weight discrimination as a legitimate form of prejudice,” she said. “It is comparable to other characteristics like race or gender that already receive legal protection.”

In the study, on average, 5 percent of men and 10 percent of women reported suffering from weight-based discrimination. But these averages obscure the true extent of the problem, the study concludes — the same statistic, for individuals of a BMI of 35 and above, skyrockets to 40 percent, the study found. BMI, or body mass index, measures an individual’s percentage of body fat, based on his weight and height.

Puhl said weight discrimination was found to occur both in institutional settings such as workplaces, where overweight individuals were at greater risk for being denied jobs and promotions and being fired, and in individuals’ interpersonal relationships, where such individuals were more likely to be insulted, mistreated and harassed.

The data also revealed a significant gender divide: Women are twice as likely to report weight discrimination than their male counterparts. While men do not begin experiencing a significant level of weight discrimination until they reach a BMI level of 35 of higher, women develop a high risk at a BMI level of 27 — evidence that the societally “acceptable” weight standards for women are more stringent than they are for men, the study found.

For highly overweight individuals, this gender gap in discrimination is exacerbated, the study showed. Women with a BMI of between 30 and 35 were up to three times more likely to report weight discrimination than their male peers of a comparable weight.

The study, conducted on nearly 3,000 adults ranging from age 25 to 74, used data from self-reported weight discrimination and compared it to discrimination based on race and gender. Participants were asked questions about the forms of, and reasons for, the discrimination they encountered in their everyday lives, Puhl said.

Tatiana Andreyeva, co-author on the study, said weight discrimination, particularly for women, is more prevalent than discrimination based on sexual orientation, nationality or ethnicity, physical disability and religious affiliation — but receives less public attention than many of these other biases.

Puhl’s study is among a slowly growing body of research on a phenomenon that has only just begun to enter the radar of policy — and lawmakers. Despite its high prevalence, research on the subject remains sparse, and limited data are available on the types and patterns of weight discrimination, Andreyeva said.

In addition, Puhl said, legal measures that protect overweight and obese people from discrimination do not currently exist, but they are desperately needed if change is to be had, she said. Currently, no federal legislation exists to outlaw weight-based discrimination, and Michigan is the only state that has enacted legislation at the state-level, she explained.

A bill that would make it unlawful to discriminate against a person based on weight or height received a public hearing in Massachusetts this month, but the results from that hearing have not yet been released, Adreyeva said.

“Without meaningful legislation, it is likely that weight bias will remain socially acceptable,” Puhl said.

While anti-weight-discrimination legislation might partially alleviate the problem, it alone cannot solve the problem, she said — understanding why weight stigma arises may also offer some long-term solutions.

Although there exists little research on the reasons for weight discrimination, Chelsea Heuer, research assistant at the Rudd Center, said the dominant model has to do with the psychological-attribution theory.

This theory hypothesizes that individuals tend to ascribe negative attributes to individuals who are overweight, which results in blame — a sort of “punishing-the-victim” tactic, she said. Conservative, North American ideals, such as individualism and self-determinism, exacerbate the prevalence of these attributions, she added.

“People in our culture believe that people get what they deserve,” she said. “So, since weight is seen as a controllable factor, people assume that [overweight individuals] have some sort of problem with them.”

Indeed, studies show that weight stigmatization is less severe in cases in which individuals’ weight is associated with factors outside their control, such as medical problems, instead of factors like overeating, Heuer said.

Other studies point to changing the dominant social environment as key: Data show that if a person perceives others around him to be more accepting of obesity, he is more likely to be similarly accepting. Hence — according to Mirian Berg, president of the Council on Size and Weight Discrimination — the next step is to challenge the pervasive cultural paradigm that thinness means good, while being overweight means bad.

“We have to first get to the point where people don’t look at an overweight person and assume they are lazy, unhealthy or any of the other stereotypes that exist,” she said.

Puhl said that education — both about the phenomenon of weight discrimination and the more deeply ingrained idealization of thinness — is key to changing how people think.

In a review published by the Rudd Center in 2001, weight discrimination and stigmatization was found to be prevalent in three areas of living: employment, education and health care. According to that review, 28 percent of teachers said becoming obese is the worst thing that can happen to a person, 24 percent of nurses reported being “repulsed” by obese patients and, controlling for income and grades, parents were found to invest fewer college funds in their overweight children than their thin children.