I would reccomend you reading a book which is mainly focused on bodybuilding but the author of the book learned how to make that diet since he used to work with diabetes type 1 and 2 patients. The book you can find if you search in google for scivation books and read either the lean mass diet or the lean muscle cut diet. The diet it has in it works very well for improving insulin and keeping it at a constant level, since it includes healthy fats in every meal almost.
Hope that helps.
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