Image of blackboard with brain drawing & roast me saying 'feed me'
A general rule for me now is minimal carbs, no grains, no seeds, no legumes, no nuts! No leafy greens.
I do some inquiry when I'm out, like what fats do you cook in? And if it's processed oils I don't put that in my body. I really want to live a long and healthy life and I'm giving my body the best chance I can by being proactive with my food. Ill pick some ripe fruit from a tree or take organic fruit from a local friend. Not much either, I know that my body works really well without fibre, fruit for variety is the only reason why I do it. 
When it comes to feeding my brain the same rules apply. If my brain isnt right the rest of me isn't either. It's a commitment for sure, but I see myself healthy and very happy, and free in my body.
Diets these days that are deplete or deficient in essential fats, DHA, EPA, and healthy saturated fats, have deficiencies in fat soluble nutrients, performed vitamins A, D3, E-complex and K2. 
They have amino acid imbalances, and deficiencies in other key animal sourced nutrients like B12, the most usable B vitamin.  
Such a diet and its related deficiencies lead to over arousal, or up-regulation, and lead to  anxiety related disorders, memory problems, cognitive dysfunction, sleep disorders, brain degeneration, neurological disorders, gastrointestinal disorders, and utter metabolic chaos.
If it's maintained long enough the damage is irreversible. We have record numbers of Parkinson's disease now, Depression is rampant, and up- regulated people move faster without awareness, they are more inclined to be angry and not sleep deeply. It's a bad recipe for sure.
  • Blood sugar influences the functioning of the brain, hormones and neurotransmitters. The neurotransmitters are the main mood and brain regulators. 
  • Surges of blood sugar generate depletion of the neurotransmitters; serotonin,epinephrine, norepinephrine, dopamine and GABA. 
  • Blood sugar surges also deplete B-vitamin complexes which are needed to manufacture the neurotransmitters.
  • Blood sugar also depletes magnesium, which is needed for parasympathetic function, (relaxing the body) , liver detoxification, and DHA synthesis.
When we eat foods that stimulate us or we are sensitive to this stimulates cortisol production and in turn causes over arousal.
A brain that is reliant on sugar surges will get compromised when things in the diet are compromised. But a brain that is reliant on ketones will remain steady, and not have any vulnerability.
We know that oxidised food is not good to consume. Oxidisation is another word for rancid. And we wouldn't eat rancid food intentionally. But oxidation happens internally as well, it targets key cells in the body.
Blood sugar surges accelerate glycation or oxidisation. Thus deteriorates cell function. The brain is particularly vulnerable to the ravaging effects of glucose, which diminishes its delicate structure, and its functional capacity. 
When the brain is exposed to gluten it accelerates the damage.
Once the brain is on a downward spiral of damage it loses its mitigation capacity and today we have anxiety and anxiety related disorders now at epidemic proportions.
By removing or reducing our dependence on glucose for fuel we can change our  body’s ability to stay healthy on all levels. Staying healthy and optimal is about, for me, having the best life experience possible.
Asking yourself today: what can I do to make myself healthier and happier? 
Re-framing questions like this can be useful in changing the brain's objectivity. Replacing negative self-talk with positive statements or direction has a huge impact on brain chemistry. 
Creating hormone release that is calming and downregulating the body and not keeping the body in high arousal and taking all the associated anxiety that goes along with that.
I suggest meditation, sleep, no bright screens after dusk, self pleasure or slow caring intimate connection with your partner. 
No one will be more invested in your health and well being than you.