Doctors have a specific definition of what it means to be overweight or obese.

But that’s not how it works on the beach, on Tinder or at the workplace.

In the social world, people’s gender, race and generation matter a lot for whether they are judged as “thin enough” or “too fat,” according to a new Cornell study.

In other words, “it looks like obesity is in the eye of the beholder,” said co-author Vida Maralani, associate professor of sociology.

“People are judged differently depending on who they are,” she said. “‘Too fat’ in the medical world is objective. You can measure it. But in the social world, it’s not. It’s subjective.”

The study appeared April 19 in Sociological Science. Maralani’s co-author is Douglas McKee, senior lecturer in the Department of Economics.

Many studies have linked obesity with poor socio-economic outcomes like lower wages, family income, marriage rates and spousal earnings. But this study is different, because it looks at similar measures both over time and across gender and race.

The researchers analyzed wages, family income and the probability of being married for each of four social groups: white men, black men, white women, and black women. The study’s sample includes nearly 6,000 people who were teenagers when they were first interviewed in 1979 and just over 6,000 people who were teenagers or young adults when they were first interviewed in 1997. Each group was surveyed again seven years later.

In both the 1979 and 1997 groups, white men had better outcomes when they had a mid-range body mass, as opposed to being either quite thin or very overweight. For white women, the thinner they were, the more likely they were to be married and have higher family income and wages.

“We find quite consistent patterns for white Americans across outcomes and over time. For white men, there was a penalty both for being too thin and for being too fat. For white women, thinner was nearly always better,” Maralani said.

For African-Americans, the researchers found the patterns changed over time. The 1979 groups had been more similar by gender – the white and black men were similar, and the white and black women were similar. But in the 1997 group, that pattern shifted.

“For African-Americans, the link between body mass and these outcomes dissipates by the late 1990s; people seem to have become more accepting of larger bodies. But that’s not true for whites,” Maralani said.

For all four social groups, the relationship between body mass index (BMI), a measurement calculated from weight and height, and the likelihood of being married weakened across generations. “As average BMIs increase for all groups, it may be that our acceptance of marrying partners who are larger necessarily shifts as well,” the authors wrote.

One of the more notable findings of the study was just how much society expects white women to be thin: “The patterns for all women in the 1979 cohort and white women in the 1997 cohort remind us that norms of thinness dominate in women’s lives at work and at home,” the authors write.

And white women get judged more than men not just for being fat, but for being anything bigger than thin. The higher a white woman’s BMI, the lower her wages. Conversely, white women with the lowest body mass had the highest wages.

The patterns for white men are consistent with a body norm too – one that’s not too thin and not too fat. “I think our focus on the medical definition of obesity has led us to lose track of the fact that, in the social world, we have quite subjective and fluid definitions of what it means to be fat or thin for different groups.”