“Don’t do cardio. You'll lose your gains”. Any budding fitness enthusiast would’ve heard this a million times, especially in the super-competitive world of gym bros. The logic of that sentence goes something like this: if you do too much cardio training, you will lose the muscle mass you’ve gained from strength training. Another version of this runs something like this: you do cardio to lose fat and strength training to build muscles. And never the twain shall meet.
A new study effectively busts that myth. According to researchers of the University of New South Wales, who published their finding in Sports Medicine, strength training alone is enough to burn fat. This analysis of previously published studies found that you can lose 1.4% of your body fat from strength training alone. This is pretty much the same amount as when you do cardio.
"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 favourable loss of body fat without having to consciously diet or go running," says Mandy Hagstrom, an exercise physiologist and one of the authors of the report.
The researchers went through 58 research papers to measure the outcomes of strength training programmes. They found that participants in these research programmes worked out for about 45-60 minutes a day, nearly 3 times a week, for about 5 months. In this time, on average, the participants lost 1.4% of their body fat.
Despite this finding, the researchers say that an exercise regimen should maintain a good balance between cardio and strength training. This is because, cardio exercises help increase stamina and is ultimately great for the health of the heart. "More often than not, we don't gain any muscle mass when we do aerobic training," says Hagstrom. "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."
Some fitness coaches have long been saying this, making the point that strength training can burn fat and build muscle. One of them is Jeff Cvaliere of Athlean X. Here’s a video of busting the same myth that that the researchers have demolished.