In June 1959, by the time of the Congress of the SA Medical Association in East London, I felt that I had done enough study to point out how sugar and other fibre-stripped foods would seem to have played a predominant role in the emergence of diabetes and obesity in urbanised Zulus-having detailed the exact differences between the diets of rural and urban Zulus. 2 This study was set out in detail in a later work3 with the relative commonness of these conditions in the urban milieu as compared to that of the rural people. I felt confident that Zulus who had moved permanently into the large city, had not been able to adapt themselves to a dramatic dietary change occurring over the extremely short period of a decade or so, and which had thus had such serious effects upon their metabolic systems after these few years' exposure'.

At that 1959 Congress, I also delineated a reasonably exact'Incubation Period'for diabetes, 2 and formulated the" Rule of20 Years" amongst people moving permanently from areas of poor nutrition into the urban fibre-stripped foods milieu. This also strongly suggested the overwhelming effect of dietary environment as there were invariably no family histories in these people. This' Incubation Period'was later also confirmed by workers in Israel and Iceland. By this time, as someone imbued with the'impact'theory of a high refined carbohydrate intake on the body's metabolic system, I had completed in 1960 an exhaustive review of average per capita annual intakes of sugar intakes in