Do skinny wives make for happy marriages?

(CBS) Does a thin wife make for a happy marriage? A new study shows that marital satisfaction is higher for husbands when their wives are skinnier than they are.

What about wives? Are they happier when hubby is thinner? Actually, no. Wives are also more satisfied when they're thinner than their husbands, the study showed.

But the study's lead author says women don't have to be thin in absolute terms to have a happy marriage - just thinner than their hubbies.

"There's a lot of pressure on women in our society to achieve an often unreachably small weight," study author Andrea Meltzer, a doctoral candidate at the University of Tennessee, told ABC News. "The great take-home 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."

For the four-year study, Meltzer and her colleagues studied 169 newlywed couples, mostly Caucasian and all age 35 or younger. The researchers found that husbands were more satisfied initially when their wives had a lower body mass index (BMI). The wives who had a lower BMI became more satisfied over time.

Meltzer told CBS News that there is likely an evolutionary basis to men's initial satisfaction with a relatively thin partner - because women with a lower BMI may be more likely to be fertile than women with higher BMIs.

But why would wives be more satisfied when their husbands' BMIs are higher? Meltzer hypothesizes they're more satisfied because their husbands are.