Just curious if anyone has a theory;
I am 45 y.o., used to be a distance runner, run approx 4 days a week now 4-5 miles.
I am about 5"10, 150lbs. I was always skinny, slight frame. Got fairly out of shape in early 40s, ie; lost definition, slight stomach fat.
Over the last year I seem to have transformed for no apparent reason. I have gained much lean muscle mass, lost body all kinds of body fat.
No diet change really, the only difference is I do pull ups/chin ups maybe twice/wk. I always used to lift weights, which Ive cut out now. ??