You've moved the goalposts IMO, from the idea of being able to simultaneously gain muscle and lose fat with any particular diet and exercise regimen, to being able to simultaneously gain muscle and lose fat at any particular point in time. The former being what everyone means when they say they lost fat and gained muscle, the latter being a mostly useless concept.
But that study does implicitly contradict even the latter. The subjects were fed hypocalorically and had a net negative change in weight, yet gained lean body mass, implying at least some of the lean mass gain was fueled by metabolizing stored fatty tissue.
I think when using the word "simultaneously" I fairly implied I am talking about metabolism (growth/breakdown) with respect to a point in time not over time.
>The former being what everyone means when they say they lost fat and gained muscle...
Again interpreting me fairly... I don't think anyone argues fat/muscle can not be gained or lost at varying rates resulting in net gains and net losses respectively over time.
>the latter being a mostly useless concept.
No more than understanding chemical reactions result in release or taking in energy. Sure for most people broad sweeping changes to diet and exercise will result in positive net changes to weight and MBI...but to athletes trying to gain muscle while not losing cardio, body builders cutting weight for a show, MMA/boxers making weight for a fight...these useless concepts come into play. Further, its not just world class athletes, to even the average joe going to the gym, these concepts are important to aid in maximizing gains, minimizing recovery times and improving overall performance when working out.
But that study does implicitly contradict even the latter. The subjects were fed hypocalorically and had a net negative change in weight, yet gained lean body mass, implying at least some of the lean mass gain was fueled by metabolizing stored fatty tissue.