According to a study published in Obesity, women who were dating gained an average of 15 pounds over five years, women who were cohabiting but not married gained an average of 18 pounds, and women were married gained an average of 24 pounds. Men also gained weight, but there was no difference in the dating and cohabiting groups.   So how does this happen? Those who are in the dating pool often do activities together that revolve around food and drinks. They eat meals at restaurants, grab a drink at the bar, and indulge on sweets together.   According to researchers from the University of Toronto, the average meal at a sit- down restaurant contains 1,128 calories, not counting appetizers or dessert. Pair a meal with a cocktail or two, and it’ s easy to see why you can start to add inches to your waistline. Research shows that women tend to gain weight when moving in with a guy, often because his food habits start rubbing off on her. It can be difficult to resist new junk food in the house, and couples that live together often cozy up on the couch in front of the TV while eating take out food together.    Although 70% of engaged women try to lose weight before their big day, once the wedding is over, the weight tends to creep back on. And this isn’ t just limited to the women. Research conducted by Andrea Meltzer of SouthernMethodist University found that spouses – both male and female – who were more satisfied with their relationship tended to gain more weight, while spouses who were less satisfied tended to weigh less. Spouses may also gain weight because they associate their weight with their appearance – something that often  becomes less important once they’ ve settled down – over their health. Having children in a relationship also can cause parents to gain weight who may turn to food to help handle stress. They may also eat with children, and then again later when their spouse gets home. But gaining weight can negatively affect your relationship, even if you gained the weight because you’re in a happy relationship.   According to Rachel Dinero, an associate professor of psychology at Cazenovia College, “ Weight gain can lead to emotional distress and less interest in sex.” Luckily there are several ways that couples can get their weight (and health) in check.   When you’ re in a relationship, men and women often eat the same meals as their significant other. But even at the same height, men will burn more calories than a woman because they naturally have more muscle mass, which requires more fuel.   Consider how many calories you should be eating based on your body size and activity level and realize that it will most likely be different from your significant other. If your partner wants to get take out from somewhere unhealthy, stop by a second place with healthier options on the way home. You can still enjoy eating together even if the food is different. Or better yet, cooking at home together will most likely save you calories and money.    Although couples tend to pick up on each other’ s habits, there may be times when it’ s smarter for your waistline to stick to your habits. Don’ t feel obligated to eat with your partner if you’ re not hungry. You can politely say that you’ re not hungry and still keep them company or sit with a cup of tea.   Similarly, there may be times when you have to prioritize your habits over your partner’ s habits. If they sleep in late and you usually wake up early for a work out, it can be tough to get out of bed. But keep your goals in mind and remember that your habits help you achieve them.   Couples can also use the pursuit of health to grow closer together. Studies have shown that working out with a partner can help you drop more weight than those who work out alone. Couples who work out together are also more likely to stick to a work out program.   You can also plan activities together that are active. Go for a hike or bike ride together. It doesn't have to be an intense work out – just something to get moving. Although research suggests that relationships do tend to make people gain weight, remember that it’ s not just about physical appearance. It’ s about health, too.   Communicate your health needs and goals in your relationship so you can stay healthy with each other longer – and enjoy the occasional indulgence together.