Metabolism—the complex biochemical process by which your body converts everything you eat and drink into energy—is a hot topic among exercise and weight loss experts, especially after the recent viral news that contestants on The Biggest Loser almost universally gained back the weight they’d lost. The primary culprit? Their respective metabolisms, which slowed down for years—years!—after competing on the show.
That news didn’t shock Brooklyn Bridge Boot Camp founder and clinical nutritionist Ariane Hundt, though. “They took their metabolism to the absolute max, were stressed, malnourished, and completely wrecked their hormonal balance,” Hundt says. “The general approach is ‘the more we exercise and the less we eat, the better we’ll look,’ but that model is going to create serious damage.”
So what does work when it comes to revving up your metabolism? And how can you make sure your exercise regimen isn’t backfiring?
Here are five ways to make your workout actually work for your metabolism.
1. Aim for intensity and variety
Your body gets conditioned to exercise pretty quickly. If you keep up a steady schedule of, say, 60 minutes of moderate-intensity running a few times a week, you’ll soon start to burn fewer calories within that time. “You have to challenge the body to need more from its energy pathways,” explains Jaime Schehr, RD, ND, who’s also the founder of XFitLab, a service that does metabolic and other performance testing for athletes. Schehr recommends incorporating High Intensity Interval Training (HIIT) into your routine, and regularly changing up your workouts so your body doesn’t recognize and adapt to the work you’re doing.
2. But avoid overdoing it
Hundt agrees that HIIT training is awesome when it comes to boosting metabolism—but within reason. Intense exercise puts a lot of stress on the body, so she recommends restricting it to three days a week, with lower-intensity workouts like yoga and Pilates as well as plenty of recovery in between. Otherwise, you’re going to get into a Biggest Loser situation where the nonstop pressure of the program affects your hormonal balance and leads to exhaustion and cravings. Plus, chronic stress messes with your nervous system, which regulates metabolism. Hundt’s rule of thumb? “Work hard if you’re well-rested and have energy,” she advises. “If you’re stressed, go easy.” Simple, but so easy to forget.
3. Think less cardio, more strength training
Because your body requires a lot of energy to maintain muscle, building muscle can raise your resting metabolic rate. And that means you’ll burn more calories even when you’re not sweating. On the other hand, with intense, sustained cardio, like marathon training, “your body no longer just burns sugar or fat; it’ll burn muscle as fuel,” Hundt warns. “When you’re done with the race, you have less muscle and a slower metabolism than when you started.” That’s not to say you shouldn’t run marathons; just stay on top of your cross-training, too.
4. When you work out (and what you eat after) matter
Schehr tell clients who are looking to boost their metabolism to work out in the morning on a relatively empty stomach, then eat or drink something with lots of protein right after. “What we know is that when you exercise in the morning, you speed up your metabolism throughout the day by having more of a caloric burn,” she says—and the protein will help your body repair muscle efficiently. Of course, if after trying (and trying) you’ve come to realize that early workouts just aren’t for you, or going to the gym on a relatively empty stomach makes you totally hangry, this strategy’s not going to work for you. Which brings us to…
5. Listen to your body
Hundt says your body is constantly letting you know how it’s doing, via your appetite, cravings, and energy level. If any of those are out of whack, your metabolism likely isn’t performing well either. “There is something to be said about working with your body to find the tipping point where you continue to see progress and keep your metabolism in check,” she says. Ditch the “more is more” mindset and really tune into your body, then give yourself permission to adjust and meet its unique demands. Your metabolism will thank you.