It’s cold out there. And running on the treadmill sucks. And, wait: you also just remembered that you actually hate running. But if you’re trying to lose fat, and you’re not willing to spend endless time running and jumping, you’re out of luck, right? Maybe not…there’s a new study out there that seems to suggest that you don’t actually need to do a ton of cardio to burn fat. Sounds good, right? Now, we’re not saying you don’t have to exercise at all to burn fat, but the old conventional wisdom that to gain muscles, you strength train, and to lose fat, you do cardio might not be all that wise, after all. Cardio haters rejoice: a recent study is busting myths, offering compelling scientific proof that cardio isn’t the only way to get leaner.
The Debate That We Just Can’t Seem to Settle
Cardio or weight training? Which is better? Might as well ask whether the chicken or the egg came first, because we actually just don’t know. But a common thing you hear in the exercise world is that cardio (like running, cycling, or swimming) is the best thing for losing weight or improving heart health, and resistance training (like weightlifting) is the best thing for building muscle (though without any cardiovascular benefits). But is that really the case?
Up until now, there really haven’t been any conclusive studies on the best type of exercise for getting rid of some of that pesky body fat. Why? Well, to be honest, there’s not much money in researching exercise – actually, it’s pretty expensive to conduct sports science studies. Getting people to follow an exercise plan requires quite a bit of money, especially when you’re also doing some complex analyses, so many studies in the field have too few participants to make a solid conclusion.
It’s also just really difficult to run the studies and get trustworthy results. If you recruit people who are already fit, your findings will be less impressive and the conclusions less generalizable. But if you recruit untrained people, you might end up with no result because the subjects didn’t understand how to do the exercises well enough.
So have we learned anything before this year about the benefits of cardio versus resistance training? Well, there have been a few notable studies. For example:
- One study from 2017, which followed over 100 obese people who were randomly assigned to do cardio, weight training, both, or nothing, found that people who did some cardio saw a bit more improvement in heart health than people who did only resistance, and the people who did any resistance training improved more in terms of lean muscle mass and bone density. But nothing much could be determined by this small study: the change in lean muscle mass between the cardio and resistance groups differed by less than 1%. So really all that was learned was that if you start from nothing, making any change will result in some sort of improvement – not exactly groundbreaking.
- Even when researchers do try to gather data comparing resistance training and cardio, there’s not all that much to look at: for example, researchers conducted one review in 2018 of more than a dozen studies showing that cardio improved health, but only a handful compared cardio and resistance, and those lacked enough evidence to draw any conclusions at all.
- But one meta-review looking at multiple studies in 2011 did find some mentions of how exercise can affect visceral fat, or the fat that builds up in your torso and is thought to be the primary driver of obesity-related disease. The review found that cardio provided benefits in this area, but when compared to resistance training, the data, unfortunately, was inconclusive.
Hm. Not exactly helpful, right? If you’re trying to lose fat, it’s kind of like you’re either stuck doing the same old cardio routine, or you’re hoping for the best – or you’re so anti-cardio that you’re just not doing anything at all. But enter a new study that could give you some hope.
Lift Weights, Lose Fat?
A study published in Sports Medicine in September this year might finally be providing some answers – and busting some myths – about exercise and fat-burning. According to senior author of the study Dr. Mandy Hagstrom, exercise physiologist and senior lecturer at University of New South Wales (UNSW) Medicine & Health in Australia, “A lot of people think that if you want to lose weight, you need to go out and run. But our findings show that even when strength training is done on its own, it still causes a favorable loss of body fat without having to consciously diet or go running.”
Wow, really? Yup – and it looks like this study blows other ones out of the water for accuracy and reliability. Dr Hagstrom and her team pulled together the findings from 58 research papers that used highly accurate forms of body fat measurement (like body scans, which can differentiate fat mass from lean mass) to measure the outcomes from strength training programs. Altogether, the studies included 3000 participants, none of whom had any previous weight training experience, and most of whom worked out for roughly 45-60 minutes each session for an average of 2.7 times per week for about five months.
And what did they find? The research team found that the participants lost, on average, around 1.4% of their body fat, or a little more than a pound of fat, through these strength training only programs, which is similar to how much you might lose through cardio or aerobics. As Dr. Hagstrom points out, “Resistance training does so many fantastic things to the body that other forms of exercise don’t, like improving bone mineral density, lean mass, and muscle quality. Now, we know it also gives you a benefit we previously thought only came from aerobics.”
That’s very good news for the cardio haters out there. And while Dr. Hagstrom still encourages people who are looking to lose fat to eat right, and do a combination of cardio and resistance training, she also acknowledges that these findings might be just what some running-resistant people might need. “If you want to exercise to change your body composition, you’ve got options,” she says.”Do what exercise you want to do and what you’re most likely to stick to.”
Change Your Relationship with Your Scale
But there’s something else that Dr. Hagstrom encourages: changing how you see the numbers on your scale, and how you look at weight loss. Why is it that many of us don’t see strength training as a way to get rid of fat? Probably because we’re too focused on “losing weight,” or seeing the numbers on the scale go down.
But that’s not really the right way to approach things: it should be more about getting lean, and changing your body. Stepping on the scale only tells part of the story: you might change the numbers more by doing tons of running or cycling, because you’re burning fat, but when you lift weights you’re burning fat and gaining muscle. That means that the numbers on the scale might not be changing all that much, but your body is!
According to Dr. Hagstrom, “More often than not, we don’t gain any muscle mass when we do aerobic training. We improve our cardiorespiratory fitness, gain other health and functional benefits, and can lose body fat. But when we strength train, we gain muscle mass and lose body fat, so the number on the scales won’t look as low as it would after aerobics training, especially as muscle weighs more than fat.”
“If you’re strength training and want to change how your body looks, then you don’t want to focus on the number on the scale too much, because it won’t show you all your results. Instead, think about your whole body composition, like how your clothes fit and how your body will start to feel, and move, differently.”
This study might not show us everything we need or want to know. For example, it didn’t look at whether variables like exercise duration, frequency, or intensity impacted fat loss percentage, but the research team does hope to next investigate whether how we strength train can change the amount of fat loss. But even just the information it has provided us with is pretty groundbreaking, and a great first step toward learning so much more about how strength training can change our bodies.
And it might be very welcome news to you that cardio isn’t the end-all-be-all of health and fat loss – just remember, as with everything, it’s all about balance. Get moving, get lifting, get cooking healthy, whole foods, and you’ll be heading in the right direction!