Think before you bite. Drinking lots of water keeps will keep you from snacking when you're not hungry, and it gives you more energy. The tough part with exercise, of course, is getting out there and doing it. If exercise doesn't make the list you won't do it. Any time that you'll do it.
Some people prefer a walk and a bath as a nightcap.
Others find that noontime workouts free them from finding a sitter for the kids. As far as making exercise a habit, however, science is on the side of the early birds. Find a passion. Keep an exercise log. Set a goal.