It’s been recognized for years that many people choose spouses or domestic partners like themselves – similar social class, similar education level, similar relative height, same race or ethnicity and so on.

Now scientists at the Rowett Research Institute and University of Aberdeen have discovered that we also choose partners who share a similar body fatness with us.

If this is true, overweight couples may be passing on to their children two copies of the genes that make them susceptible to being overweight or obese.

The researchers believe this may be a factor in the obesity epidemic.

As published in the August 2007 issue of the Journal of Clinical Nutrition, this study used dual-energy X-ray absorptiometry (DXA) to measure the body fat of 42 couples.

The researchers found that a person’s amount of body fat was similar to that of their mate. It didn’t matter how long the couple had lived together.

Why does this happen?

The scientists aren’t sure. But they suggest that people who are overweight or obese may participate in the same social activities and meet that way.

Also, people marry when they’re older these days and they become fat younger. So it’s easier to find a partner with a similar amount of body fat.

In the 1940s and 1950s, people married younger and were less likely to be obese when they did. So even if someone was destined to become obese at a later age, their partner wouldn’t know it at the time they wed.

The researchers believe these trends may have contributed to the obesity epidemic because people can now choose partners with the same body fat composition more easily.

I’m not sure I buy this argument.

It may be true in some cases. But I’ve known a lot of couples with one skinny partner and one fat partner.

Over time, if both partners became fat, it seemed more likely that they adopted the same eating habits, not that they were attracted to each other because of body fat composition.

But that’s just my opinion. I don’t have a study to back it up. The Aberdeen scientists do, even if it only involves 42 couples.

What do you think?

Are you more attracted to people with the same amount of body fat as you have? Do you think that plays a role in how you choose a domestic partner?