I am confused too. It seems like you answer allready to half of your question

but anyway, you preserve muscle eating enough
protein and saying enough, I mean at least 400gm /day. If you want to keep size or to build size don't do too much aerobic. Other else you will shape yourself a soccer player physique of or even worst an marathon runner one. Three sessions per week are just fine. On the morning on empty stomack. It will help you more on your
fat loss program.