My opinion is that it is mostly impossible. There are certain times where you can, like if you have never worked out before or are regaining lost muscle, or if you are obese enough that you have an almost limitless supply of energy to provide your system. Still, even in those cases it is very unlikely to be as efficient as splitting the process into parts. The main problem is that the mechanisms and pathways in the body to deal with a deficit and to build muscle are not only different, but are antagonistic, so it is extremely self limiting.
And quite honestly, without Dexa scans, it’s nearly impossible to know, over anything but a significant period of time, what changes in body composition have come about. And even with, the margin for error on Dexa is not good enough to pick up small movements.
Bottom line is that the human body follows all laws of science, including those about conservation of mass and energy, and torque vs weight etc. Any time we assume that a body can do something outside of those rules, we are probably wrong, or just are mistaken in our assumptions.