After examining the results of 25 separate studies, they concluded that obesity does have a denigrating effect in the workplace, with the weight-based bias stronger for sales positions than for managerial positions.
"There are a whole set of stereotypes that go along with being overweight, and a lot of them transfer into the workplace in terms of people's judgment about others' abilities and appearance in relation to job performance," researcher Cort Rudolph said in a statement.
The researchers found the results of all the studies examined were consistent in finding that people who are overweight are viewed more negatively in the workplace than those who are of average weight.
The bias was felt most when overweight people applied for a job and went through the initial selection process with body weight found to be less of a factor at the performance evaluation stage, and with stereotypes having a minimum influence when it comes to promotions.
Rudolph said this was not surprising based on what was known about weight-based stereotypes.
"Some of the basic stereotypes associated with being overweight include laziness, sloppiness, untidiness and lack of self-discipline and control," he said.
"Overweight people are also regularly labeled as having increased health problems, which is an issue often considered cumbersome by organisations."
But Rudolph, who will present the study's findings at a conference of the Society for Industrial and Organizational Psychology in San Francisco in April, said there was good news for overweight employees.
"The bias effect tends to decrease as people's tenure with an organisation increases," he said.
Rudolph said this was an issue that could become more a problem as Americans became heavier.
"Considering this growth, stigmas associated with body weight can become more and more of an issue," he said.