If you’ve ever said something like “I want to tone up” or “I want to lean out,” you were referring to body recomposition, even if you didn’t know it. Body recomposition — or altering your physique by burning fat and gaining muscle at the same time — is a different approach to health and fitness than the typical weight-loss mindset.
Many people think that true body recomposition is impossible because of this conundrum: To reduce your body fat, you have to eat fewer calories than you burn. But to build muscle, you have to eat more calories than you burn.
Your body is smarter than you may give it credit for, however, and by keeping a close eye on your diet (specifically when you eat what) and your training, you can absolutely lose fat and gain muscle at the same time.
Excerpted from CNET