Having an attractive husband makes women more likely to diet, a study has shown.

Women chose to slim down because they did not want to look bad compared to their other half, researchers said.

But men who had an attractive wife did not have the same problem. The researchers blamed social pressures and said that men need to tell their partners they are attractive just the way they are.

The study involved questioning 113 US couples who had been married less than four months and were aged in their late 20s on average. The couples also posed for photographs which were rated by volunteers. 

The study found that women judged more attractive than their husbands did not experience pressure to diet. But those who were less attractive were more likely to want to lose weight. Men, by contrast, had a low motivation to diet regardless of how attractive their wives were.

The study, published in the journal Body Image, was carried out by doctoral student Tania Reynolds and assistant professor of psychology Andrea Meltzer of Florida State University. 

Reynolds said that the results showed that "having a physically attractive husband may have negative consequences for wives, especially if those wives are not particularly attractive". 

She added: "One way (for men) to help these women is for partners to be very reaffirming, reminding them: 'You’re beautiful. I love you at any weight or body type'."