After getting married, people are less likely to exercise and more likely to gain weight, says a new study. Researchers from the University of North Carolina at Chapel Hill examined data on about 8,000 young men and women from teen years to young adulthood and found that those who got married or moved in with a romantic partner were more likely to gain weight or lead sedentary lifestyles. However, past research has shown that when one spouse takes steps to improve his or her health and lifestyle, the other often follows suit.