In the study led by a University of Strathclyde academic, participants were asked to rate people for their suitability for jobs in the service sector, based on their appearance.
Researchers found even marginal increases in weight had a negative impact on female candidates' job prospects.
Professor Dennis Nickson, who is based at the University's Department of Human Resource Management, said: "Many organisations in the service sector, such as shops, bars and hotels, seek to employ people with the right 'look' which will fit with their corporate image.
"This study, though, shows how women, even within a medically-healthy BMI range, still face discrimination in service sector employment."
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Theresearch, published in the journal PLOS ONE, was carried out in partnership with University of St Andrews academics Dr Andrew Timming and Professor David Perrett - of The Perception Lab - and the University of Toronto's Dr Daniel Re.
"We found that women, even within a normal BMI range, suffered greater weight-based bias compared to men who were overtly overweight.
"The findings raise a number of practical implications, both ethically and from a business point of view. Ethically, the results of the study are deeply-unsettling from the viewpoint of gender inequality in the workplace, highlighting the unrealistic challenges women face against societal expectations of how they should look.