These are just a tiny subset of the studies done - google scholar can find you many dozens more, if you desire. And, of course, the fact that these studies exist it all necessarily implies that you lose muscle mass when in energy deficit, as you will see in the control groups for them.
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For protein intake helping decrease this: https://faseb.onlinelibrary.wiley.com/doi/abs/10.1096/fj.13-...
https://faseb.onlinelibrary.wiley.com/doi/epdf/10.1096/fj.13...
https://faseb.onlinelibrary.wiley.com/doi/epdf/10.1096/fj.14...
https://www.sciencedirect.com/science/article/pii/S216183132...
https://www.mdpi.com/2072-6643/12/8/2457
For weight lifting helping decrease this: https://www.mdpi.com/2072-6643/11/11/2824
https://journals.physiology.org/doi/full/10.1152/japplphysio...
https://link.springer.com/article/10.1007/s00726-013-1506-0
https://journals.physiology.org/doi/full/10.1152/ajpendo.005...
https://onlinelibrary.wiley.com/doi/abs/10.1002/mus.21780
https://journals.physiology.org/doi/full/10.1152/ajpregu.004...
https://www.mdpi.com/2072-6643/10/4/423
These are just a tiny subset of the studies done - google scholar can find you many dozens more, if you desire. And, of course, the fact that these studies exist it all necessarily implies that you lose muscle mass when in energy deficit, as you will see in the control groups for them.