The answer lies in the fact that white flour in general either replaced more nutrient-dense foods or that in a context of a low mineral, high sugar diet, white flour was disastrous for teeth. Had white flour been consumed with cod’s heads and cod’s liver, or raw milk cheese the results would be different. (Note: I do not advocate white flour consumption.) Rather white flour was consumed generally with sugar in the form of pastries, or with jam and jelly on toast.
