Any serial dater knows the drill: Fall in lust over cocktails and dinner dates; fall in love over takeout and movie marathons. Whether you call it a "love handle" or "happy fat," as your affection grows, so can your waistline.
"They’ve found the person they plan to spend the rest of their life with, and if they’re thinking about their weight in terms of appearance, they’re going to let themselves go a little bit," says Andrea Meltzer, a psychologist at Southern Methodist University whose study last year found that satisfied newlyweds gain more weight in the first four years of marriage than those who are less happy with their unions. Other research has linked marriage with weight gain and divorce with weight loss.
But coupling up is no excuse to ditch a healthy lifestyle or to maintain an unhealthy one. Quite the opposite, says Lennie Carter, a financial manager in the District of Columbia who has run 25 marathons with his husband. "Being in a relationship sort of forces you to take care of yourself so that you’re healthy for the other person," he says. "You want to set a good example for each other."
Indeed, happy and healthy pairs do exist, Meltzer says. What’s their secret? "They are probably thinking about their weight in terms of health," not appearance, she suspects.
Be Open to (Positive) Change
In her work as a personal trainer in Northampton, Massachusetts, Kelly Coffey sees how much significant others can influence her clients’ health – for better or worse.
"I’ve had many clients whose partners seem to be totally invested in sabotaging any healthy effort they make, because eating crappy food and unhealthy ways had become such a part of their relationship," says Coffey, who blogs about her own health challenges and successes at www.strongcoffey.com. "They took my clients not doing that as a personal affront or a judgment."
Coffey is on to something: In a recent study of how cohabitating couples handled one partner’s weight loss, researchers found that some relationships grew tense after one in the pair slimmed down. Why? The partners who didn’t lose weight sometimes felt nagged to do so, resented that their loved ones were changing or felt threatened because they were used to being "the skinny one" or "the one who exercised," says Lynsey Kluever Romo, a communications professor at North Carolina State University and the study’s lead author. "There was this dark side to weight loss," she says.
But the bright side that most couples in the study reported positive changes in their relationships after one partner lost weight, such as better and more frequent sex, feeling closer to one another and enjoying more shared activities. The partner who didn’t lose weight often improved his or her eating and exercise patterns, too. "You can either decide to be responsive and supportive, or resist that change," Romo says. "And resisting the change can cause conflict."
[Read: Helping Your Spouse Lose Weight? Feed Him Support.]
Talk it Out
Weight, eating patterns and body image are sensitive issues – even to broach with someone as close as a spouse. But whether you want to break your late-night ice cream habit or finish a triathlon, talking about health concerns and goals with your partner is key to achieving them, experts say.
"Instead of considering these topics taboo, people need to get more practice and get better at engaging them," says Charlotte Markey, a professor of psychology at Rutgers University and author of the forthcoming book "Smart People Don’t Diet." In her ongoing research with same-sex couples, Markey’s finding that lesbian pairs are generally healthier in terms of weight management than gay couples – in part because women tend to be more communicative. "They’re more likely to talk about these issues and facilitate conversations that are conducive to behavior change," she says.
If you’re the one concerned about a partner’s health, voice your concerns gently. For example, say, "I’m worried about my health, are you worried about yours? What can we do together?" Markey suggests. Or, "I love you no matter what, but you seem to be upset about this. Is there something I can do to support you?"
If you’re the one embarking on a healthy lifestyle change, talk with your partner about your plans and suggest ways he or she can support you – say, by keeping the kitchen cookie-free or by joining you on weekly bike rides. And, be clear that, while your shared routines might change, it’s no reflection of how you feel about your partner or the relationship. As Coffey puts it, "That I’m loving myself doesn’t mean I love you any less."
[Read: How to Improve Communication With Your Partner.]
Find Common Ground
Carter, the marathoner, wasn’t a runner when he met his husband, Charlie Divan, 18 years ago. But after Divan convinced Carter to join a local running club, the sport became central to their relationship and social lives. "It’s one of those things you build into your lifestyle," Carter says.
Similarly, Angela Meyer, a yoga instructor and regional director of group exercise at the YMCA in the District of Columbia, shares a love of fitness with her boyfriend, who coaches her in martial arts. "Every night we’re either training or teaching some sort of movement," Meyer says. "So it’s nice because it’s kind of our happy hour."
For couples who aren’t already gym buddies, trying a new activity together – be it rock-climbing, ballroom dancing or joining a Frisbee league – can improve your relationship as well as your health. Classic psychology research supports, for example, that married couples are more satisfied with their relationships when they pursue more active dates like hiking than those who settle in for a more mundane activity, such as watching a movie on the couch.
"It becomes about more than just the exercise; it’s something you share, something you can talk about and be curious about," Meyer says. "It’s a way to spend time together."
But you don’t have to train together to stay together. Coffey, for one, has tried cycling with her husband, and he’s tried weightlifting with her. Neither enjoyed the other’s passion. "We shook hands and parted ways," Coffey says. Now, she takes care of their two toddlers when he’s on long rides, and he tackles the dishes and laundry to give her time to lift.
Such support is key, experts say. "If your relationship is happy and supportive, it’s going to extend to benefits in your mental and physical health," Markey says. "Healthy relationships tend to equal healthy partners."
SEE ALSO: How Your Diet Is Stressing You Out