In the Upanishads it is said that food after digestion is divided in three parts, one part applies to the body, one to the mind and one is rejected. How food becomes mind -or influences the mind- is a very interesting process and Ayurveda, the ancient medical science, elaborates in detail about it.
In its present conditioned state the soul is reflecting its consciousness through the mind. Mind is matter, ego is also matter, intelligence is also matter, but they are all conscious because of the presence of the soul, and this consciousness is everywhere in the body. At first it happens in the mind, then it spreads into the other parts of the subtle and physical bodies.
Consciousness can become influenced by food according to the quality of matter. Just like electricity generates a type of light according to the type of bulb, it can be yellow, white, small, big, more powerful etc. In the same way, consciousness can be sattvic (in goodness), rajasic (in passion) or tamasic (in ignorance) from the type of food we eat, the kind of energy we get from it and how it comes into the body, into the mind, into the cells. You can be a gentle person, you can be rough, a criminal, an angry person, or you can be peaceful. All these are manifestations of consciousness which is influenced by food, this is an amazing thing. Therefore it is said that we are what we eat.
The first step to get a benefic food for us starts in how food is produced, for this reason we are promoting and practicing bio agriculture and cow protection.