It is that simple, really. For years I have regarded students as a vivid video monitor of their home life. Man is a product of his environment. TV plays a huge part in this drama. The average child watches that idiot tube over five hours each day.
Most sensible parents agree that most TV programs are junk.
For years doctors and scientists have known that the human body needs certain nutrients, vitamins, etc. to remain healthy. Omit any of those items and a problem will probably develop. The two major items that have caused problems in my classroom are sugars and caffeine. Both speed a child's activity. Sugar is brutal when its supply is exhausted.