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Male jurors are more likely to find obese women guilty than lean women, but they didn't show the same weight bias against their own gender, a Yale University study found.

Researchers showed 471 study participants a photo of one of four people - a lean woman, an obese woman, a lean man or an obese man - and asked them to determine whether that person was guilty of an imaginary check fraud crime on a scale of 1 to 5. Men were more likely to find the obese woman guilty than the lean woman, and the results were statistically significant.

"I think it's one more nail in the coffin of how painful it is for people that are of larger sizes," Lynn Grefe, president and CEO of the National Eating Disorders Association. "These people could be healthy. We're judging people. We're making stereotypes. We did this with race years ago. We did it with religion."

She added that while obese people are perceived as lazy or sloppy, people should remember that obese people don't choose to be large. They may have medical problems, different genes or a newly identified mental illness associated with binge eating.

Click here to read about another bias women face.

Lead researcher Natasha Schvey said she and her team controlled for age and attractiveness by using the same woman twice and photo-shopping her to be both lean and obese. They did the same for the men.

Schvey said she'd read about weight bias in other settings, such as office environments, but wondered whether it existed in the justice system.

"This seemed like a critical gap in the literature on weight stigma," Schvey said, adding that it's not clear whether negative socioeconomic perception based on body mass factored into the results. "Since this is really just the first study of its kind, we just wanted to determine whether or not something might be going on."

Ultimately, she said, the results were "disappointing but not entirely surprising." Men tend to judge women more harshly than men, and women tend to be more sympathetic. The female study participants showed no weight bias.

"I think [it may be] because many women have gone on diets and had difficult times, and they're not meeting their weight goals," Grefe said. "I think they're more understanding. A piece of it is [that] they feel sorry for them because they've been through it themselves."

Grefe thinks there should to be anti-discrimination laws on the books for weight just as there are for race, religion and sexual orientation.

But women can take some comfort in the fact that mock jury studies isolate specific factors that rarely make their way into actual jury verdicts, said Paula Hannaford-Agor, the director of the Center for Jury Studies.

"Most studies of actual jury trials show that the weight of the evidence is the single most important factor affecting jury verdicts," Hannaford-Agor said. "Factors such as victim, defendant and juror demographic characteristics only account for a negligible portion of variation in jury verdicts."