Even marginal weight increases have a negative impact on women's job prospects, a study has revealed.

Researchers found women face weight-based prejudice in the workplace even when their body mass index (BMI) is within the healthy range.

The study found applicants for customer-facing positions were particularly affected but those applying for roles in offices and stockrooms also faced discrimination.

Men were also subject to discrimination over their weight, but to a far lesser degree than women.

The study was led by professor Dennis Nickson from the University of Strathclyde's department of human resource management.

He 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."

Academics from the universities of St Andrews and Toronto also contributed to the research, which has been published in the journal Plos One.

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 waiting or as a sales assistant, and for a non-customer facing role, such as a kitchen porter or stock assistant.

Participants were told that applicants were equally-qualified and were shown faces that reflected a "normal" weight and a subtle "heavier" face.

Professor Nickson said: "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."