This is Scientific Americans 60 Second Science.

I'm Erica Barris.

Got a minute?

Bridget Jones in print and on screen called them the smug married.

The happy couples that seem to have it all.

But maybe the fictional Jones should have called them the plump married because along with offering couples unbridled bliss,

marriage can cause them to pack on some extra pounds.

That's according to a study in the Journal of Family Issues.

Sociologist Jay Teachman at Western Washington University

examined data from the national longitudinal study of youth.

The data included info about more than 3,000 African Americans over a 20 year period.

Teachman tracked body mass index, BMI, a measure of obesity from adolescents

to middle age. And he analyzed the relationship between BMI marital status and changes in marital status.

It turned out that living without a partner usually equated to being thinner

and having a lower BMI compared with married people and couples living together. The single folks included the never married and divorced.

Both men and women gained weight,

but when it came to race,

black women had the most rapid weight gain,

followed by white women and then black and white men.

The weight gain was just a few pounds, but even a slightly higher BMI is associated with weight-related

health issues.

Several reasons exist for the weight discrepancy between the single and married people.

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