Exactly why is it that married people get fatter? Last week I explored one piece of the problem, looking at how our mates' feelings, and our perceptions of those feelings, can sabotage diets. The marital weight issue reemerged two days later, this time in The New York Times' "For Better or Worse, for B.M.I." Citing statistics on the partnered vs. the single, this item detailed how the partnered indeed gain more weight over time than singles. It noted, though, that those who are actually married gain even more than those in unmarried relationships. This holds true for both women and men.

Researchers tend to explain these differences in terms of lifestyle. They speculate that those with partners become more sedentary, contend with post-pregnancy weight, perhaps eat out more often. Commonly, also, they point to incentive. (This reminds me of a cartoon with a jubilant bride kicking up her heels-"Hurray, no more weight watchers!!") What's implied, of course, is that we try harder to look good when we haven't landed a mate. "Why try so hard afterward?"

I think a better question is "Why is it so much harder to care for yourself after marriage?" For a healthy diet and a weight bring more than just mate-landing good looks. They also support better physical health, longevity, vitality, and self-esteem. Lifestyle factors and reduced incentive certainly can contribute to marital weight gain. But as the sabotaging partner issue makes clear, there's a lot going on in relationships that can complicate things. And shouldn't having a partner make self-care easier, at least in some ways?

Sometimes, caring for oneself and attending to others feels fundamentally incompatible. And for many this remains true even without practical issues to solve-like finding time to exercise when you've got kids.

I recently explored this issue with 40-something businesswoman I'll call Rita. She'd spent several years during her teens and twenties caring for a very sick mother. She rarely took time to attend to her own needs, fearing that her mother would suffer in pain or feel unbearably bereft in her absence. Recently, Rita's older partner has suffered bouts of illness. During this time it has seemed nearly impossible for Rita to stick with a diet plan essential to her own health. When her partner is doing well, the food preparation and planning goes smoothly and easily. This is not a matter of Rita's partner insisting on fattening meals, bringing sweets into the house or demanding unreasonable amounts of attention. Rita is coming to realize that she simply doesn't, and sometimes feels she can't, focus on herself, when feeling vigilante about someone she loves.

While the conflict between caring for oneself and others may seem like a more feminine issue, it's not necessarily restricted to women. An overweight single father I know (I'll call him Brian), feels that he just can't keep good food in the house. His kids like the cookies and chips, he'll say. He feels he can't insist on more home dinners, even though he and his teens are all capable cooks. There's just too much else to do, he feels, even on weekends. He realizes that these explanations don't make perfect sense. But he says, "When they're at their mother's, it's just so much easier. When they're here there's just so much going on." It's been hard for him to grapple with how guilty he feels when he asserts his own needs in the presence of the kids, as if they'd really suffer if he limited the junk food at home or said "no" to eating out more often.

For some, weight clearly fluctuates with relationship status-weight rises when in relationship and falls when not. While many factors obviously contribute to this pattern, I often notice it among those who tend toward overresponsibility for their "others". These same people may gravitate toward, or attract, "others" who do less and need more from their mates. It's hard then, indeed, for any focus to remain on such things as carving out exercise time or experimenting with healthier cooking.

So we might think of maintaining one's weight after marriage as part of maintaining post-marital health. And essential to that is attending to how we care for ourselves day in and day out as we remain attentive to our mates. This could prove as important as keeping up with dental care and regular check-ups-things for which we often do maintain our "incentive" .