Gets mish-mashed into the component amino acid building blocks and neurotransmitter precursors. Now you are trying to get taken up by the brain from the blood , amino acids for building functional brain tissue, but dopa with one extra hydroxly group on the aromatic ring of it's structure (something that a brain enzyme acting on absorbed tyrosine must do anyway, before we get any dopamine) has to do it metabolically anyways. Thus, every amino acid that is roaming in the vicinity of the blood brain barrier is either allowed in or it's not.
Dopa has to "compete" with absorption of all other essential amino acids,and pharmacologics dictate that less dopa gets into the CNS when blood concentratins of other amino acids are high.
Eat meat when your body is purged of other food, and in small amounts. WE get enough protein in our western diet to kill a horse so to speak, so one must hardly ever worry about protein consumption, just when it has proven to be opertune times to eat meat; none if you're a vegetarian (perhaps best), 4-6 oz/day of anything from prime rib to baked clams, otherwise
A spartan diet is usually in the wings for a pwp, because inactivity leads to easy weight gain. Among a whole host of things like heart trouble, (clot formation, and cardiopulmonary weakness) have to do with lifestyle.
My suggestion
Rome is burning, grab a fiddle and give it your best shot