Nice, as somebody in the nutrition field, who has studied this extensively, I can say that Daz is right on the money. There are more nutrients in whole grains (i.e. magnesium, calcium, copper, B vitamins, zinc, etc), however because of the high anti-nutrient content (phytates and lectins for example), poor absorption of nutrients in whole grains, and the poorer digestion in general (compared to refined grains), modern research is suggesting that there is a net-loss in nutrition, especially in mineral status. Refined grains such as white flour, white rice, etc, are neutral, and thus not harmful, especially when balanced with other macro nutrients to slow the spike in blood sugar. The best carbs to consume are well-cooked tubers/potatoes and soft easily digestible fruits. Not only are they nutritionally superior, but they are more easy to digest and don't contain anti-nutrients like whole grains do. And if you are going to eat grains, do like the Asians do and consume them refined. Not all refined foods are bad, and in many ways improve health.
Slowly, there is a body of scientific literature suggesting that we should be consuming foods that are easy on digestion, foods that do not result in gas and bloating. Eating starchy foods that have not been processed or cooked enough, results in less cellulose or amylopectin breakdown, and makes it harder for our digestive systems to process and extract the nutrients. In addition, this decreases intestinal transit time, allowing food to sit in our small intestine for longer than desirable, which research shows can result in the inappropriate persorption of allergenic proteins as well as increase the proliferation of lipoploysaccharides in the bloodstream by the excess production of endotoxin from bacteria.
The goal then, should be to consume a diet that is easily digestible, and that results in BMs that are frequent and pleasant. Fully cooking food will help this process along. It is no surprise that many anthropologists believe that cooking made us human. The advent of cooking corresponds the the increase in brain size and development as a species.