Increasing muscle mass is not impossible. We are doing it all the time. Some of us are shrinking as well. Burning fat gaining it. A 6 foot big moose doesnt have a small head and didn't start out that way with a big head when he emerged from his mom's vegines.
Yes brains do grow. As they are assigned and connected to control and command more bodily functions aka muscles u never knew you had, more brain matter and neurological connections are made.
Problem: heat and energy drain.
It would actually be more efficient to do away with brain matter and have less to run on, less heat, less dead weight.
