04/12/2008 05:12 am ET Updated Nov 17, 2011

Love Lard: Why Relationships Make You Fat (And How To Keep That From Happening)

Theresa's not the only one to fall victim to "love lard" (the weight gain that often accompanies falling head over heels). Last April, researchers at Newcastle University looked at studies that examined the eating habits of over 12,000 cohabitating or married couples in Europe, North America, and Australia. In a trend called "dietary convergence," they found that after a twosome begins to cohabitate, women start consuming more junk, while men's diets tend to improve.

But why do we pork out when we pair up? "Your guy has food that you'd never bring in your house," says dietitian Lisa Young, PhD, author of The Portion Teller Plan. "But half the battle is recognizing that this could be a problem and being proactive about it." Read on to get the skinny on the most common weight issues--and how to keep them at bay.

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