Perform total-body strength training.
“The type of exercise you select is very important,” Milton says. “Cardiovascular exercise works on aerobic muscle fibers, which will increase oxygen extraction, but not necessarily change muscle mass. And you may still lose muscle mass if that’s the only way you’re trying to lose weight.”
However, while strength training is most famous for building muscle while in a caloric surplus, myriad studies show that resistance training is effective at attenuating declines in muscle mass when in a caloric deficit.
Milton explains that, unlike aerobic exercise, strength training—especially heavily-loaded strength training—primarily recruits type 2 muscle fibers, which contribute to muscle mass preservation and gains. Strength training also triggers the short-term production of hormones such as human growth hormone and testosterone that aid in muscle retention and building.
“At a minimum amount, people should perfect whole-body resistance training three days per week,” Campbell says. “Ideally, however, they should strength train five to six days per week, splitting their schedule into upper-body days and lower-body days.” What’s more, to make sure that you are optimally stimulating muscle growth, Smith-Ryan recommends performing loading exercises with roughly 80 percent or more of your 1RM, or the max weight that you could lift for one rep. Aim to perform 6 to 8 reps of each exercise in your workout routine, staying on the lower end for compound exercises and the higher end for single-joint isolation work.