The American workforce is particularly unkind to heavier women.

The more overweight a woman, the more likely she is to work a low-paying job, according to a new study by the Vanderbilt Law School. And that contrasts with overweight men, for whom the correlation isn’t nearly as strong.

“For women there’s this really clear pattern,” said Jennifer Shinall, the study’s author. “Starting when a woman is overweight, she’s less likely to work in what’s known as a personal interaction job, which tends to pay better. And it only gets worse from there – morbidly obese women are the least likely to work those jobs.”

To gauge the way that a worker’s weight correlates with his or her pay, Shinall used data from the American Time and Use Survey and Current Population Survey. Doing so allowed for a comparison between job types and weight types. Specifically, the study focused on how male and female weight classes – normal-weight, overweight, obese, and morbidly obese – correlated with one of two job types: personal interaction jobs and physical activity jobs. Personal interaction jobs, which include sales and communications positions, tend to be higher paying than average; physical activity jobs, which include home health aid, day care and food preparation positions, tend to be just the opposite.

Women, the data show, are increasingly less likely to work the higher paying jobs and increasingly more likely to work the lower paying jobs as they become heavier. Men, on the other hand, see no such gradual effect. “No matter the occupation, obese men seem to do just as well” as normal-weight men, Shinall said. “That’s just not the case for obese women.”

The reasons for the disproportionate effect that women’s weight appears to have on their employment are unclear. Beauty, or attractiveness, have long been tied to better pay, both among men and women. Everything from one’s height to one’s hair color and fitness have been found to affect one’s career.

Economist Daniel Hamermesh has written a book about the correlation between attractiveness and compensation titled “Beauty Pays: Why Attractive People are More Successful.”

In this particular case, it’s reasonable to think that the selection process for consumer-facing jobs is what puts heavier women at a disadvantage, Hamermesh said.