A new study by a University of Utah anthropologist suggests that earlier beliefs of an hourglass figure being the ideal body type for women may be wrong. The recent study suggests that women who have flatter hips have strength, assertiveness, competitiveness and an ability to cope with stress as their share of benefits.

Elizabeth Cashdan, an anthropologist at the University of Utah, said although hourglass-shaped women enjoy greater fertility and health, they may be less able to ensure the survival of their children in subsistence cultures. "This is about trade-offs," Cashdan said. "The human body is a compromise. Take the ideal skin color. If you have light skin you have less risk of being deficient in vitamin D, but on the other hand you are at greater risk of melanoma."

According to her study published this month in the journal Current Anthropology she says it's due to the hormones. The hormones that make women physically stronger, more competitive and better able to deal with stress also tend to transfer fat from the hips to the waist resulting in a higher waist-to-hip ratio, or WHR.

"The hormonal profile associated with high WHR [high androgen and cortisol levels, low estrogens] may favor success in resource competition, particularly under stressful and difficult circumstances," said Cashdan. The women who had more of an apple shape not only had more strength, assertiveness and the ability to cope with stress but they were the breadwinner in the family as well.

"All of these effects could be adaptive in circumstances where women must work hard to support their children, compete directly for resources for them, and cope with resource scarcity," Cashdan writes. "A truly optimal level of hormones, then, should weigh these considerable advantages against their well-known costs: lower fertility, health problems if overweight, and possibly lowered attractiveness to men." Androgen increases assertiveness, competitive aggression and muscle mass, while cortisol enhances the ability to tolerate stress.

Karen Brunger, a body image consultant and founder of the International Image Institute in Ontario, Canada said, "In the past, a woman's world went from her father's home to her husband's home and she wasn't expected to make a living. The more hourglass she was, she could expect to marry well, but that is no longer the case. The hourglass body doesn't work for us. A lot of my work with women has been to help build self esteem and honor the bodies they have," she continued. "In the past, women were their bodies. Now it is about what we're doing in our lives and who we are as people."

Cashdan's study also noted that the idea of what constituted an ideal body type differed from culture to culture. In societies such as Japan and Greece where women are less economically independent, the males tend to prefer thinner waists than in northern European countries with greater gender equality. "Many of us who have worked with people in non-Western economies, where women are breadwinners and provide for the children, we have found that women have more apple-shaped bodies," Cashdan said. "And when you ask men about their preferences, beauty is important but they want a hard-working woman."