Elizabeth Cashdan of University of Utah said in societies and situations where women are under pressure to procure resources -- to support themselves or their families -- they may be less likely to have the classic hourglass figure.
Studies have shown that a curvy waist-to-hip ratio of 0.7 or lower is associated with higher fertility and lower rates of chronic disease and studies have also shown that men prefer a ratio of 0.7 or lower when looking for a mate.
Cashdan compiled data from 33 non-Western populations and four European populations and found the average waist-to-hip ratio for women is above 0.8. Androgens, which include testosterone, increase waist-to-hip ratios in women by increasing visceral fat, or belly fat, Cashdan explained.
"The androgenic effects -- stamina, initiative, risk-proneness, assertiveness, dominance -- should be particularly useful where a woman must depend on her own resources to support herself and her family," Cashdan said in a statement.
The study, published in Current Anthropology, found in Japan, Greece and Portugal, where women tend to be less economically independent, men place a higher value on a thin waist than men in Britain or Denmark, where there tends to be more sexual equality,