Spending hours upon hours on the treadmill can be downright dull. After an extended period of time, the same old exercises are going to wear out their welcome. Variety is the spice of life -- so be sure to mix it up regularly. For starters, find a balance of strength training and aerobic activity. Do light weight lifting two to three days a week. Perform a variety of moves that work the various muscle groups. More muscle equates to more weight loss - muscle burns more calories than fat, even when you're resting. You stoke your metabolic fire when you build muscle. Take a Pilates or weight lifting class. On the other two days, swim, jog or participate in another aerobic activity.