In the study, 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.
"A key element of a person's look is their weight. Workplace discrimination against those of anything other than 'normal' weight is not new. A large number of studies have highlighted how people who are obese or overweight suffer from bias when they look for employment.
"This study, though, shows how women, even within a medically-healthy BMI range, still face discrimination in service sector employment."
The research, 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.
The study asked 120 participants to rate eight pictures of men and women for their suitability for jobs working in a customer-facing role, such as a waiter or sales assistant in a shop, and for a non-customer facing role, such as a kitchen porter or stock assistant.
Participants in the study were told that applicants were equally-qualified and were shown faces that reflected a 'normal' weight and a subtle 'heavier' face.
Professor Nickson added: "The results found that both women and men face challenges in a highly 'weight-conscious' labour market, especially for customer-facing roles. However, women faced far more discrimination.
"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.
"From a business point of view, we would argue that employers should consciously work against such prejudice and bias by providing sensitivity training for those responsible for recruitment."