U.S. researchers have found that ovulating women have an urge to cut their calories and maintain a slim figure to look attractive to men. The researchers say the drive to maintain less weight is stronger when the women are most fertile, as compared to other times of the month.

Previous studies found that women do change their eating behavior during ovulation. Researchers have suggested that this behavior was due to certain physiological changes in the body, primarily due to an interaction between the nervous and hormone systems.

The latest research has attributed a psychological factor as well.

"In our research we saw that shifting levels of hormones interacted with women's desires to manage their body attractiveness, which predicted an important behavior - eating less," said lead researcher Andrea Meltzer, of Southern Methodist University in Dallas, in a statement. "These findings illustrate that broader social norms that dictate that thin women are more attractive can play a role, in addition to physiological factors."

The study was conducted by the researchers in three phases. In the first experiment, the researchers found that women who were not taking hormonal contraceptives desired to lose weight during ovulation periods.

The second experiment -- which involved both women who took hormonal contraceptives and those who did not – showed that hormonal preparations affected the regulation of the endocrine system and such women did not have a desire to lose weight.

The third experiment involved married women who were not taking hormonal birth control pills. The researchers found that such women also were most motivated to lose weight during ovulation. But they tended to do so only when motivated to maintain the attractiveness of their bodies.