As someone who’s been 150kg and 75kg, fat, fit and everything in between I can guarantee you fat and muscle/bone do not build or atrophy at the same rate, both

As someone who’s been 150kg and 75kg, fat, fit and everything in between I can guarantee you fat and muscle/bone do not build or atrophy at the same rate, both volumetrically and temporally Bones and joints are especially slow to adapt (in both directions). Even losing ~0.25kg/w for a year is sufficient to cause my shoulders to frequently sublux if I attempt to raise my arm above shoulder height And trivially, gaining weight without proper training or too quickly can result in insufficient time for your bones and joints to adapt, placing them under potentially dangerous stress The time scale the article is talking about does not follow the same trends as recovery from sudden and complete mobility cessation (injury/paralysis) Resistance training does work at all ages, but the degree to which it is effective varies greatly, and its recommendation is potentially dangerous if applied bluntly to all people