Eating a variety of different foods help shake up a meal, especially casseroles and one-dish meal. It is as easy as adding a side of vegetables, a salad or fruit, or maybe even a whole wheat roll. Same goes with fitness, cycle through several different types of routines every couple weeks.
Eating a variety of food helps satisfy your taste bud and ward off cravings, thus snacking less. Switching up your fitness routine can help prevent the oh so dreaded plateau. All in all though variety just keeps things from getting boring!