Stress causes men to be more attracted to heavier members of the opposite sex, a study has found.

The reason may relate to feelings of insecurity and seeking protection from a mature-looking mother figure, scientists believe.

Researchers uncovered evidence of the psychological effect after testing 81 male university students.

One group was placed under stress by asking them to take part in a taxing mock job interview.

All the men then had to rate the attractiveness of photographed female bodies ranging from very thin to obese.

The stressed group found a significantly heavier body size as the most attractive.

Stressed men gave significantly higher ratings to normal and overweight figures than non-stressed men.

The range of women they saw as attractive was also shifted towards those who were heavier.

For stressed men, the threshold point after which women became too big to be attractive was higher.

Dr Viren Swami, from the University of Westminster in London, and Martin Tovee, from the University of Newcastle, report their findings in the online journal Public Library of Science ONE.

They wrote: “The present results provide the first experimental evidence that the experience of psychological stress shapes men’s judgment of female body size.

“Men experiencing stress not only perceive a heavier female body size as maximally attractive but also, more positively, perceive heavier female body size have a wider range of body sizes considered physically attractive.”

The findings lend support to the Environmental Security Hypothesis, said the researchers. This suggests that when conditions are threatening or uncertain, individuals will be drawn to others with more mature physical characteristics, including heavier body size.

“More mature physical features may communicate attributes such as strength, control and independence during periods when such qualities should be most desired,” the scientists wrote.

Previous research suggests that heavier body size is preferred when resources are scarce.