I simply cannot overstate the importance of your food choices when it comes to your mental health. In a very real sense, you have TWO brains—one in your head, and one in your gut—both of which are created from the same tissue during fetal development.
These two systems are connected via your vagus nerve, the tenth cranial nerve that runs from your brain stem down to your abdomen. It is now well established that the vagus nerve is the primary route your gut bacteria use to transmit information to your brain.
Maintaining optimal gut health is therefore paramount when trying to address your mental state. In this regard, the modern "Western" diet has several things working against it: