/sci/ - Science & Math

what determines a sedentary person's maximum muscle mass before they start working out?
I'm 6'4" and 180 lb, really low body fat. I'm gonna start working out in ~3 week after I sort out some health stuff but I'm gonna start eating big NOW to get used to it
I don't really care if the huge eating between now and when I start working out makes me gain weight only in fat, but will it actually be 100% fat? Like what if I started drinking protein shakes with creatine and stuff now (I won't do that, but just as speculation)? Is there some upper limit to your muscle mass before you body says "you need to start working out if you want more". I know building muscle occurs best after you develop microtears or something but can they grow otherwise?
the reason I ask is because my current muscle mass (and the muscle mass of most other sedentary people in their early 20s) is overkill for their lifestyles, so I don't think its limited by our lifestyles
thanks
also remember that "why can't I build muscle?" guy from like 2018? what ever happened to that guy?