Close banner

Support Outside Online

Love Outside?

Help fund our award-winning journalism with a contribution today.

Contribute to Outside
HealthTraining & Performance

Can I Really Speed Up My Metabolism?

Losing fat and boosting muscle mass can make a big difference in how you burn calories.

Cutting down on body fat speeds metabolism, but the next step required for increasing your burn rate is building muscle. (Photo: iStock)
action agility athlete body box box jump build caucasian center circuit club cross crossfit dedication endurance equipment exercise exercising female fit fitness gym health healthy indoors jump jumping lifestyle men mid-air muscular people sport sports strength training vertical wellbeing woman women workout young

Yes, you really can speed up your metabolism, though likely not significantly, and certainly not with diet pills, green tea, or any other quick-fix products. There's only real way to make a difference in how your body burns calories: increase your lean muscle mass.

To get why, you have to understand a bit of the science behind metabolism. Your metabolic rate is essentially the speed at which your body expends energy, and it depends on many different factors. Your age, weight, health history, organ function, oxygen capacity, and even your height can all influence how many calories you burn during exercise, but also (and more importantly) during sedentary times of day.

Most of your resting metabolism is taken up by your organs—brain, heart, liver, etc. But the biggest factor affecting your metabolism that you can control is your ratio of body fat to lean muscle mass. "Muscle burns more calories than fat tissue, because muscle requires more energy to maintain," says Harold Gibbons, New York State Director of the National Strength and Conditioning Association. "The more fat you have, the slower your metabolism will be."

Just dropping pounds probably won't help, though, since most weight loss is a combination of fat and muscle tissue. "Usually, when people lose weight, their metabolism actually goes down," says Kim Sasso, a nutritionist at Loyola University Health System. That makes sense; you don’t need as much food to maintain a lower bodyweight. But if your goal is simply to up your metabolism, Sasso says, "it's not until you start decreasing your percentage of body fat and replacing it with increased muscle mass, do you start to see a difference in your resting metabolic rate."

“It's not until you start decreasing your percentage of body fat and replacing that with increased muscle mass do you start to see a difference in your resting metabolic rate.”

You can see where this is going: To speed up your metabolism, you need to strength-train. And since the two biggest muscles in the body are the glutes and the thighs, lower-body exercises like squats and lunges are a great place to start, according to Sasso.

"Just by increasing their muscle mass on those two areas, you can burn more energy when you're exercising," says Sasso.

Plus, strength workouts have an additional metabolism-boosting benefit. Because this type of anaerobic training involves breaking down and building back up of muscle tissue, the body needs to burn more calories in the 24 to 48 hours after each session—a phenomenon known as excess post-exercise oxygen consumption, EPOC, or, informally, "afterburn.” Researchers, however, are currently debating how intense that afterburn really is

Cardio is still important, too. "Respiratory function is another big part of metabolism, and to increase that you need to be regularly getting your heart rate up," says Sasso. She recommends extended periods of walking, jogging, or some other form of moderate to intense aerobic activity, as well as body-weight circuit training with no rest between sets. Gibbons points out that cardio workouts generally burn more calories during exercise than strength-training—also important if your overall goal is weight loss or weight maintenance.

As far as foods and supplements go, nothing's been shown to have a meaningful impact on metabolic rate. "Green tea has a reputation for being a metabolism booster because it has compounds like caffeine, but the effect is so tiny, it's negligible," Sasso says. Protein also gets branded as metabolism-boosting, because the body uses more energy to digest it than it does for fat and carbs. But this effect is only temporary and, again, not big enough to make a real difference on its own.

Poor dietary and lifestyle choices can, on the other hand, slow down a healthy metabolism. Specifically, not eating every few hours or consuming too few calories overall, can put your body into starvation mode, so it hangs onto energy (and fat) as long as it can. Not getting enough sleep has also been shown to cause metabolic dysregulation.

Bottom line: Reduce body fat, build lean muscle mass, get plenty of sleep, and don't skip meals, so your body may burn a few more calories at rest. If you're really interested in the numbers, metabolic testing, which gauges your resting metabolic rate, can help you track your progress.

Support Outside Online

Our mission to inspire readers to get outside has never been more critical. In recent years, Outside Online has reported on groundbreaking research linking time in nature to improved mental and physical health, and we’ve kept you informed about the unprecedented threats to America’s public lands. Our rigorous coverage helps spark important debates about wellness and travel and adventure, and it provides readers an accessible gateway to new outdoor passions. Time outside is essential—and we can help you make the most of it. Making a financial contribution to Outside Online only takes a few minutes and will ensure we can continue supplying the trailblazing, informative journalism that readers like you depend on. We hope you’ll support us. Thank you.

Contribute to Outside
Filed To: Strength and Power TrainingNutritionWeight Loss
Lead Photo: iStock