The study showed that women who were evaluated as less attractive were more motivated to diet and be thin if their husbands or partners were attractive than them.
Conversely, this extra motivation to diet did not exist among the women who were more attractive than their husbands.
As for men, their motivation to diet was low regardless of their wives attractiveness or their own, the researchers said.
"The results reveal that having a physically attractive husband may have negative consequences for wives, especially if those wives are not particularly attractive," said Tania Reynolds, doctoral student at the Florida State University.
The study, published in the journal Body Image, offers productive insights about relationships in which a woman fears she will fall short of her partner's expectations.
Understanding the predictors that increase a woman's risk of developing eating disorders and other health problems could lead to earlier assistance.
"It might be helpful to identify women at risk of developing more extreme weight-loss behaviours, which have been linked to other forms of psychological distress such as depression, anxiety, substance abuse and dissatisfaction with life," Reynolds said.
"If we understand how women's relationships affect their decision to diet and the social predictors for developing unhealthy eating behaviours, then we will be better able to help them," she added.
For the study, the team examined 113 newlywed couples - married less than four months, average age late 20s, living in Dallas area -- who agreed to be rated on their attractiveness.