Composite bodies showing the average fat and muscle mass chosen as the most attractive for women (left) and men (right). Credit: Dr Ian Stephen.

A new study from Macquarie University being published in PLOS ONE has found that both genders consider an unhealthily low body fat content for women as attractive, however for men, a healthy body type with a normal body fat content, is considered more attractive.

The study used new techniques to measure different body shapes associated with different levels of fat and muscle, and then used computer graphics to apply these differences to photographs of real bodies. Participants then manipulated the apparent fat and muscle mass of these body photographs to indicate the shape that they thought looked the healthiest or the most attractive.

"In this study we found that both male and female participants chose significantly less fat mass to optimise the attractiveness of women's bodies than to optimise the healthy appearance of women's bodies," explained lead author, Mary-Ellen Brierley from the Department of Psychology. "Whereas for men's bodies, participants opted for a similar amount of muscle and fat mass to optimise attractiveness and healthy appearance," she added.

The healthy body fat range for young Caucasian women is 21-33 per cent according to previous health studies, however, research-group leader Dr Ian Stephen, also from the Department of Psychology, said that most participants selected a lower body fat range for both attractive and healthy female bodies.

"Our participants optimised a healthy-looking body composition for women at around 19 per cent fat, and a most attractive-looking body type of just 16 per cent fat. This suggests that while previous studies have found that smaller female body size generally corresponds to a greater perceived attractiveness, this observation is actually due to people's preference for lower fat mass, rather than lower muscle mass or smaller body size in general."

The manipulated female and male bodies in the study were of all of Caucasian appearance between the ages of 18 to 30, to minimise effects of age and ethnicity on participants' judgements. Notably, the participants could have chosen even thinner bodies if they had wanted, but instead chose bodies just below the healthy range.

"Perceptions of face and body attractiveness are thought to reflect the health and fertility of the person, allowing us to identify healthy and fertile mates," said Dr Stephen. "While this seems to be the case for men's bodies, our study suggests that something else is also influencing the perceived attractiveness of women's bodies. It could be that cultural ideas of the 'thin ideal' are driving down people's perceptions of attractive body fat levels in women."

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More information: Mary-Ellen Brierley et al. The Body and the Beautiful: Health, Attractiveness and Body Composition in Men's and Women's Bodies, PLOS ONE (2016). Journal information: PLoS ONE Mary-Ellen Brierley et al. The Body and the Beautiful: Health, Attractiveness and Body Composition in Men's and Women's Bodies,(2016). DOI: 10.1371/journal.pone.0156722