Before you think that your favorite boxing or spin class in under attack, let me preface this by saying that aerobic exercise can do amazing things for your body. From improving your heart health to increasing your lung capacity to the psychological effects of going on a nice long run, you should never neglect cardio completely. But with that said, the role that cardio plays in helping you shed weight is grossly overestimated. If you're performing countless hours of running, biking, or rowing with the intention of losing weight, you may be setting yourself up for failure. Here's why:
1. Your diet should be paramount.
Weight loss, after all, comes down to energy balance: Calories in versus calories out. Our bodies use energy in three ways: The first is through resting metabolism, which determines the calories you burn performing basic bodily functions—everything from maintaining a steady heartbeat to breathing to basic cognitive functions. Second is the thermic effect of food, which is what you burn simply digesting what you're eating. Finally, we have physical activity, which makes up only about 15 to 25 percent of the calories we burn.
If you look closely at those numbers, do you see the problem? The vast majority of your energy expenditure is out of your control. So if your goal is to increase your energy output to further the effects of a caloric deficit (also known as burning more calories than you consume, in order to lose weight) you may be setting yourself up for failure. What you burn is mostly out of your control, but what you take in is entirely up to you.
2. Resistance training is way more efficient for weight loss.
Lifting weights, once a practice saved only for "meatheads" locked away in dark, smelly basements, has gained traction in recent years as the preferred method of exercise. And for good reason, too. Think of resistance training as "teaching a man to fish." Let me explain:
A 30-minute jog will net you about 200 calories burned, and that's great, but it's also fewer calories than there are in a single slice of avocado toast. A workout of the same duration centered around resistance training, while burning fewer calories in the moment, will ultimately have more of an impact. Adding more muscle to your frame means increasing your caloric expenditure throughout the day, even at rest.
So while performing cardio is like fishing for the man (the man being your body), lifting weights is teaching him to fish. In other words, resistance training is turning your body into a highly efficient machine that burns more energy throughout the day—whether you're at the gym or not.
3. Doing cardio can affect the rest of your life in negative ways.
What's the word for that feeling you get after a grueling workout? Oh, right: hunger. Ravenous, insatiable hunger. You did a hard-core cardio workout in the morning, so maybe you opt for that extra bagel or treat yourself to ice cream after dinner because "Hey! I earned it!" This is called a compensatory behavior, and unfortunately, it's not a good thing. This behavior is the tendency we all have to "slow down" after a workout. So maybe in addition to that bagel, you'll take the elevator when you would normally take the stairs, or simply walk around your office less than usual, all because you feel like that spin class this morning will more than make up for it. In reality, however, you are greatly impeding your total daily calories burned, while that bagel adds a lot of calories to the other side of the equation.
4. Physical activity does not discriminate.
That 15 to 25 percent from before? That's not limited to the gym; it encompasses all of your daily activities like walking to the bathroom, standing up from your chair, and hoisting your bag over your shoulder. This is called non-exercise activity thermogenesis (NEAT), and it's a severely underrated means of burning calories. Studies have shown that making small, seemingly innocuous changes to your daily routine—whether it's opting to take the stairs, pacing while on the phone, or volunteering to retrieve that document from the printer—can have more of an impact on your energy expenditure than traditional exercise (sometimes up to 1,000 extra calories!).
And so, if your goal is to shed some pounds, you might want to think twice before you double down on the cardio. And instead, try adding some weight training to your fitness regime, mind your diet and compensatory behavior, and consider your all-day activity levels a very important part of the overall equation.
Want to maximize your workouts? Here's how to build your own pre-workout supplement.