How do additives and preservatives in processed foods affect the brain?

Yes and it affects your whole body. Junk food is high in salt, sugar and other ingredients that the body doesn't need. Without the proper foods the brain and body doesn't work correctly.

-----------

Define Junk Food. Many people in the West consider Chinese take-out to be junk-food yet the majority of centenarians (I hope I've spelt that right) come from Eastern Asia.

Junk food also contains vital fatty acids and proteins that the average person may not otherwise get. If eaten in moderation then junk foods can be a valuable addition to a person's diet.