Processed white sugar is an addictive chemical

processed white sugar has no nutritive value left. White sugar has been distilled from brown sugar which was distilled from molasses. The molasses came from sugar cane or sugar beets

 Processed sugars such as white, powdered, brown, molasses, and even honey have had some or all of their chemical bonds broken down between their basic components due to the amount of processing .

Processed sugars present as a simple potent sugar which is easily and quickly absorbed by the body.

Continuous large doses of sugar and/or carbohydrates, overtime, usually cause the brain's endorphins sites to slow production or close sites to regulate the amount of endorphins in the brain.

When the body cuts back on endorphin production it reduces the amount of endorphins available in the body at any given time. The lack of enough endorphin in the brain causes slight to deep depression. 

To maintain a normal level of endorphins in the brain the individual must eat more sugar and/or carbohydrates to get out of depression and maintain a normal mood level. This causes a vicious cycle of addiction

when processed sugar is stopped there are two chemical related reasons for the resulting depression. There is  glut of insulin depressing the system and the lack of endorphins in the brain.