Mintz on the "flavor-fringe":

Most great (and many minor) sedentary civilizations have been built on the cultivation of a particular complex carbohydrate, such as maize or potatoes or rice or millet or wheat. In these starch-based societies, usually but not always horticultural or agricultural, people are nourished by their bodily conversion of the complex carbohydrates, either grains or tubers, into body sugars. Other plant foods, oils, flesh, fish, fowl, fruits, nuts, and seasonings- many of the ingredients of which are nutritively essential - will also be consumed, but the users themselves usually vie them as secondary, even if necessary, additions to the major starch. This fitting together of core complex carbohydrate and flavor-fringe supplement is a fundamental feature of the human diet- not of all human diets, but certainly enough of them in our history to serve as a basis for important generalizations. (S.P.)

So it is all 'filler.' Or is it all sugar, once you chew your boring potatoes?