Hi @Terry4, thanks for your thoughtful post.
My objective in switching from fat to carbs was to reverse the frightful LDL level to what it used to be, while still maintaining a reasonable control over BGL. It certainly delivered on that. The reduction in TDD is a bonus. It is, however, in line with the way McDougall treats diabetics. He says that this will happen. And it does, for me anyway.
Re the possibility of endogenous insulin: who knows, it is possible. Having said that, I needed to drop my insulin injections rapidly within the first 10 days of switching from fat to carbs, to avoid hypos. It would be coincidental, but entirely possible, that the pancreas was relieved to not be force-fed fat, and started producing some homegrown insulin.
If I do eat a fatty meal, my sugar goes up (normal), but stays up for 24-36 hours (abnormal). Hence my statement that fat makes me insulin resistant.
I found my lab reports from when I was diagnosed. C-peptide was 0.3 ug/L. The fasting reference interval is 0.8 - 3.4 ug/L. I don't know how to convert that number into the US equivalent.
Never a dull moment!