Sorry I'm so late to this thread: I'm a type I (developed at age 27) and my onset was almost identical to what you described: I got really heavy, then lost something like 75 lbs. It was ugly: I wouldn't wish ketoacidosis on anyone.
What I denied in my head I finally had to accept when I was getting up three times a night to urinate while drinking no less than six liters of water. Every night. When I finally went to the doc, my fasting bg was 880. I should have been dead.
Point being that, no, diet in and of itself doesn't cause the disease. It does, however, exacerbate efforts to control it and live a longer life. And predisposition to the disease is heavily genetic.
Great post. I have a Type I ping list, if anyone here wants to join up. Not a lot of volume.
Here we have a perfect combination for testing this theory, Islanders eating western food, and westerners eating organic foods. Note that here in Israel we get the Island food type of western food as it all has to be shipped overseas. As an example, all the cereals are branded made in america, for export only. The burito shells all last a year, not a few weeks as they are laced with much higher than normal preservatives. I suspect that the preservatives are a very important key to this puzzle.
The Amish eat organic foods with NO preservatives.