1. Build muscle. Since fat is burned in your muscle, you want to activate as many muscle fibers as possible. Weight training increases lean muscle mass, which raises the amount of calories your body uses, even when you're at rest. What's more, since there's less fat in your body (and your muscles), blood moves better so you have more energy -- without eating more food. So if you haven't been incorporating strength training into your fitness routine, now is the time to start!

2. Start eating! "Your body is a 'refuel as it goes machine,' which simply means it needs to be consistently fed to provide energy to live," explains Mark MacDonald, author of the bestselling book Body Confidence. "This type of consistent feeding stabilizes your blood sugar levels and creates internal hormonal balance" -- and that keeps you from packing on the pounds. His advice: Eat within an hour of waking to kick-start your metabolism. Then keep eating every three to four hours ending an hour before bedtime.