1. Make Some Extra Muscle
Lift weights three times a week
It's the fastest way to build muscle and get results when the scale is stuck. "Research shows that regular strength-training can increase your resting metabolic rate by up to 8 percent," says Wayne Westcott, Ph.D., fitness researcher in Quincy, Massachusetts, and author of Get Stronger, Feel Younger. In an eight-week study, women and men who did only cardio exercise lost 4 pounds but gained no muscle, while those who did half the amount of cardio and an equal amount of strength-training shed 10 pounds of fat and added 2 pounds of muscle.
If you already strength-train, shorten the time you linger between sets. "Taking a brief, 20-second break after each set burns extra calories and accelerates metabolism more than waiting the standard 60 to 90 seconds, studies show," says Westcott.
Do double-duty moves
Trade exercises that isolate a single muscle, such as biceps curls, for multijoint, multimuscle moves like chest presses and squats. "The more muscles you engage at once, the more calories you'll burn," he says.
Break up your meals
If you're losing weight (and therefore muscle) by cutting calories, eating five small meals instead of three large ones helps keep metabolism high. Spreading calories throughout the day "keeps blood sugar levels even and controls the release of insulin that can cause your body to store more calories as fat," says Leslie Bonci, RD, MPH, director of sports medicine nutrition at the University of Pittsburgh Medical Center. "And every time you eat, your metabolism speeds up to digest the food."
2. Outsmart a Plateau
It's a common scenario: The first 10 or 20 pounds come off easily, but then the scale won't budge. Plateaus can happen in as little as 3 weeks, according to Drexel University researchers. As you drop weight, your body doesn't have to work as hard simply because there's less of you to move around, says Michele Kettles, MD, medical director of the Cooper Clinic in Dallas. That means your workouts produce a smaller calorie burn. For example, if you weigh 180 pounds and lose 35, you'll melt about 100 fewer calories in an hour-long cardio class—which can slow down further weight loss. And as you get older, injuries or arthritis can make it difficult to do vigorous, high-impact activities that help compensate for this calorie deficit.
Get your heart rate up
Watching TV or reading while you exercise can lower your workout intensity—and your calorie burn. Instead, pay attention to your pulse, suggests Kettles. For best results, stay between 60 to 80 percent of your maximum heart rate. To estimate your MHR, subtract your age from 220. Then multiply your MHR by 0.6 for the lower end of your target heart rate zone and by 0.8 for the upper end. For example, if you're 40, aim for 108 to 144 beats per minute. (For easier tracking, invest in a heart rate monitor.)
The more comfortable you become with a routine, exercise class, or fitness DVD, the less effective it gets. To continue to lose weight, you need to challenge your body in new ways. "Even replacing one exercise can create enough of a surprise to keep results coming," says Kettles. Try this: The first week of every month, do a new upper-body exercise; the second week, a new lower-body one; the third, a new abs move; and the fourth, a different type of cardio (cycling instead of walking, for example).