If you've managed to drop a few pounds this January, you're not going to like this news: The less you weigh, the fewer calories your body needs and ends up burning to function. Unlucky for you, keeping weight off can be even harder than losing it in the first place.
To find out whether exercise mitigates this totally unfair weight loss penalty, researchers from University of Alabama at Birmingham recently put 140 overweight women on an 800-calorie-per-day weight-loss diet and one of three supervised exercise programs: One group had to do 40 minutes of cardio on a treadmill three times per week; one group did resistance training (two 10-rep sets of resistance training exercises, including squats, leg extensions, leg curls, biceps curls, triceps extensions, lateral pull-downs, bench presses, overhead presses, lower back extensions, and sit-ups) three times per week; and one group didn't exercise at all.
When the women lost enough weight to fall into the "normal" range for body mass index, they transitioned to a less stringent diet plan designed for weight maintenance and continued to exercise as prescribed for four more weeks.
Before and after the experiment, researchers measured how much energy each woman used at rest and from moving around on her own, outside of supervised exercise sessions.
Not surprisingly, the women who didn't exercise at all were SOL: Their bodies burned fewer calories at rest than women who exercised, as expected, but also because they moved around less than they did before they lost the weight. This could be because their low-calorie diets led them to believe they had less energy, according to lead study author Gary Hunter, Ph.D., a professor of kinesiology at University of Alabama at Birmingham.
The women who did exercise fared much better: Their metabolisms slowed down a bit, as expected. But resistance trainers, in particular, ended up moving more outside the gym, and they burned more calories than the cardio groups by doing so.
While you might feel like plopping down on the couch the second you get home from the gym, Hunter says resistance training actually has the opposite effect: It gives you the strength to walk around with more ease, which enables (and evidently, encourages) you to be more physically active throughout the day. And taking a few extra steps here and there can help you keep excess weight off for good.
The bottom line is that successful dieters need all the help they can get, and working out could be just the ticket. If you don't have time for cardio and strength-training? You won't be sorry if you start in the weight room.
This article originally appeared on Cosmopolitan.com. Minor edits have been made by the Cosmo.ph editors.