New York - The secret of a happy marriage might be nothing more complicated than the wife being slimmer than her husband.
A four-year study suggests that, in the short and long term, both partners are more contented if the woman has a lower Body Mass Index.
Initially men stay in the relationship because they find their thinner partner attractive, researchers concluded.
Further down the line, women feel confident and loved because they know their man still wants them.
The study could perhaps shed new light on the break-up of Jennifer Lopez and her husband Marc Anthony, who announced last week they are splitting up after seven years together.
The 40-year-old singer is admired as much for her generous posterior as her music while her husband is noticeably thinner than her. Other celebrity matches could also back up the theory.
Model Heidi Klum - who has retained her svelte figure - married singer Seal in 2005 and they have repeatedly renewed their vows.
David Beckham and his ever-slender wife Victoria also show no sign of losing the shine from their union 11 years after the event.
The study from the University of Tennessee selected 169 married couples aged under 35 and asked them to fill in questionnaires every six months for four years.
They discovered that men who had a higher BMI, which is calculated from height and weight, were happier at the start of their marriage and stayed that way.
The same effect was true for the women - by the end of year four wives with a lower BMI than their husbands were significantly happier than those who weighed the same or more.
Lead author Andrea Meltzer said: “The great message from our study is that women of any size can be happy in their relationships with the right partner. It’s relative weight that matters, not absolute weight. It’s not that they have to be small.”
She added: “There’s a lot of pressure on women in our society to achieve an often unreachably small weight.
“One idea is that attractiveness and weight are more important to men. That might be why we see this emerging at the beginning of the marriage for husbands, and their dissatisfaction might be affecting wives’ satisfaction over time.”
Experts also suggested that men and women were happier in relationships where men are the “more powerful in a benign way”.
“The good news is there are many dimensions that symbolise power for men,” said couples therapist Susan Heitler.
Such signs could include income, intelligence, education level, height and weight, she said.
“Those signs of bigness lead to a subconscious feeling within the woman of more security and, in turn, more marital satisfaction.”
Relationships expert Jean Hannah Edelstein added, however: “I would be sceptical that most men would really reject their partners on the basis of being overweight if there were no other issues.” - Daily Mail