Strength training, cardio, Pilates, yoga…which one helps shed the pounds the quickest? The short answer: The one that burns up the most calories, most efficiently, says Michele Olson, PhD, professor of exercise science at Auburn University Montgomery in Montgomery, Ala.
Cardio is king when it comes to calorie burning, Olson says, and you'll see even better results if your workout has an 'after burn' effect.
Interval-style workouts (alternating between short bursts of high intensity effort followed by brief periods of active recovery) are one of the best ways to turn on this 'after burn,' which can raise your metabolic rate for up to four hours after a session, meaning you'll burn more calories even after the workout is over, she explains.
"Any time you elevate your heart rate into the top end of your target zone, the extra fuel (aka calories) you burn up continues in order to bring your heart rate and muscle activity back to normal and to metabolize the lactic acid you have created."
But before you jump into an all-interval, all-the-time cardio marathon, there are a few important things to note to maximize your exercise time for weight loss: First, too much high intensity cardio can burn out your body, leaving you tired, cranky, and too exhausted to stick with your routine.
To avoid this, alternate two or three days per week of higher intensity interval workouts with more endurance-focused sessions (exercising at an intensity where you can still talk without getting too winded).
Second, it's important to build metabolically active lean muscle mass to help give your body shape and definition while you continue to slim down. For best weight loss results, Olson recommends doing cardio (45-60 minutes), five days a week, along with two to three non-consecutive days of resistance training.
Arguably, the best workout for anything (weight loss included) is going to be the one that you'll do! So while calorie burn is important, find a way to make fitness fun, too. Trade the treadmill for a high-energy Zumba class or shift from weight machines to a TRX suspension trainer to prevent boredom while sticking to your workout schedule.
And, if you really want to maximize your time at the gym, consider workouts that have both a strength and cardio element to them, such as kettlebell training (a recent study from the American Council on Exercise found that total body exercises performed with a kettlebell burned a whopping 20.2 calories per minute, or about the equivalent to running a six-minute mile).
And does that mean you should skip out on the sometime less intense workouts like Pilates or yoga if you're trying to lose weight? Definitely not, says Olson. "The body thrives on new and different movements such as Pilates and yoga, so incorporate them into your weight loss efforts."
An active-style yoga class, for example, that keeps your heart rate elevated can count as a cardio session, and a Pilates class that incorporates added resistance from bands or dumbbells can count as strength training.
Finally, don't forget that it's really easy to eat back all the calories you burned off at the gym in just minutes, so for true weight loss success, couple your workouts with a healthy diet that creates a caloric deficit. To stay on track to lose a healthy and realistic 1.5 pounds per week, Olson suggests eating about 500 calories less per day and burning off an extra 300 calories through exercise.