When you're about halfway to your goal weight, Dr. Lofton recommended starting strength training to increase your metabolism further. A caloric deficit and cardio workouts should help you lose fat, which improves your metabolism; now, putting on lean muscle mass will rev it up even more. Muscle increases your basal metabolic rate, explained Dr. Lowden, which means that your body burns more calories at rest. "Higher levels of muscle mass can also increase the number of calories you burn during activities and exercise," she added. Basically, muscle equals a higher metabolism all-around. Get started with this four-week weightlifting workout plan that's tailored for beginners.