A 'white' or 'light' flour consists of only the endosperm of a grain. The high fiber bran and high vitamin germ are removed - resulting in a product that has a very soft texture, a light color and high protein. It keeps forever, but is otherwise nutritionaly sterile. Evidence of white flour dates back to 1500 BC in Egypt. At that time the expense and time it took to 'refine' a flour and produce an 'uncommon' product helped to deepen the wedge between the rich and the poor.
White flour is just protein and carbohydrate calories and a poor substitute for whole grain flour.
In the past 75 years, as refined flours have become the norm in North American housefolds, the incidence of low figer diet related diseases has risen. Cancers of the digestive system are very common and directly related to lack of fiber intake. One note, though - whole grain flours are more strongly flavored and more susceptible to spoiling due to the oils that have been retained. Keep flour well sealed in a cool place, and try to use up your supply in 3-4 months. Experiment with adding a little bit of new flour to one you're already familiar with to get used to the change gradually.