I do not think there has been any real research on diabetes. Yes there has been theories, people are trying to fit their research into the theories. The text books do not seem to fit the reality of diabetes, those without diabetes seem to have any ideas on the condition itself. Going by people own experience dealing with the medical profession, including myself. If I had listened to my diabetic nurse those years ago, no doubt, I would be on insulin, instead of diet controlled. I think Dr Aitken is right, when he mentioned that people have their tolerance levels of carbs. before they start putting weight on. For me it co insides with the change of diet recommendation of healthy eating, being carb loaded.
in my opinion and looking at the facts, We were mainly meat eaters, because of harsh environment. No way anyone could survive on carbs and veg alone in those long harsh winter conditions. Fats and protein were necessary to survive, they gave us the energy and warm, as well as maintain muscle and growth that is how we evolved. This trend has continued in other countries.