Which Is Healthier: Being Married or Staying Single?

Have you ever noticed how people tend to gain weight after marriage? Is it because people feel they don't have to try as hard to keep a trim figure? Is it because they tend to eat more regular meals? Is it because people excercise less and do more sedentary activities with their spouse, like watching TV? Is it healthier to be single and remain physically active? Or is it healthier to be married, eat regular meals and have peace of mind? Or does marriage lead to more stress? What do you think, who tends to live longer, healthier lives, married people or single people, and why?