The fix: Schedule it in. Two or three times a week, cut your aerobic workout in half and do a strength-training circuit―one set (8 to 12 reps) of five to 10 exercises for key muscle groups in the arms, legs, shoulders, back and abdomen. Taking this approach will help you begin building your body's lean muscle mass within weeks, which will boost your weight-control efforts. Not sure how to get started? Find an instructional DVD at collagevideo.com.