Can you build muscle without gaining weight?
There’s no doubt that increasing muscle increases absolute strength—but as important as absolute strength is in many sports, relative strength is often more important. While I would argue (and have) that gaining muscle (and therefore weight) is still a better way to increase your relative strength than losing fat, it can be a difficult pill to swallow. Why not gain muscle and lose fat, some argue, and thus keep your weight static?
The idea of gaining muscle and losing fat in more-or-less equal amounts is formally known as body recomposition. By itself, body recomposition doesn’t imply that the two must occur simultaneously, but to many people this is its holy grail—with simultaneous muscle gain and fat loss, you get maximum results in minimum time.
Unfortunately, holy grails rarely turn out to be more than myths; such is the case with 1 for 1 body recomposition. Over time, you can easily replace fat with muscle by interchanging strengthening phases with leaning phases—but trying to do both at the same time is a recipe for disappointment.
1 to 1 Body Recomposition: The Hypothesis
Our body stores a tremendous amount of energy in the fat. Even an extremely lean male with only 5% body fat has over 20, 000 calories locked away in their minimal adipose tissue; most people have enough fat to run non-stop from Denver to Los Angeles. Surely there’s enough energy available from the fat to power muscle growth, right?
This is the basic hypothesis behind 1 to 1 body recomposition: our body has adequate fat energy to power muscle gain without external energy being necessary. This hypothesis is simplistic, though, because it assumes that the only control on muscle growth is available energy. The truth is more complicated.
Gaining muscle (or fat) is an anabolic process while losing fat (or muscle) is a catabolic process. Anabolic processes build up molecules or structures and consume energy; catabolic processes break down molecules or structures and release energy. The sum total of our anabolic and catabolic processes is termed our metabolism.
Whenever we eat excess calories, our metabolism shifts more towards the anabolic side of the equation because there is excess energy, and in order to return to equilibrium that energy must be used either by building something or storing it. If you’re training hard and consuming more than the calories you require for maintenance, then your body will use those calories to build muscle.
On the other hand, whenever we consume an inadequate amount of calories, our metabolism shifts more towards the catabolic side; with a dearth of energy, it needs to recoup the lack in order to maintain normal function. In addition, when calories are inadequate our body begins to sequester them, naturally putting a damper on less essential anabolic processes like muscle protein synthesis.