If you read Bernstein, You will find that he believes that keeping to non-diabetic blood sugars should prevent complications.
the Medical establishment believes that complications happen despite good sugar control. To me it all hangs on the definition of "Good Control"
If that means, spending most of your time with a blood glucose reading of 1.5 - 2 times that of a non-diabetic, There's not much protecttion there. It is the level of glucose circulating in the bloodstream which does the damage.
Non-diabetics have blood glucose around 5 Most of the time and if it goes up, It drops back pretty quickly
And before anyone jumps on me to say that's not true, they might like to know that non-diabetics with high HbA1cs have a tendency to get "diabetic complications" too.
That's my main reason for believing that a target blood glucose level leading to HbA1c of 7%[average bg of about 8.6mmol/l and peaking after meals at 9 mmol/l ] is not sufficiently stringent to protect from them.
The balance of choice must be:
Are you prepared to be strict with yourself pretty much always or will you accept a greater risk of complications? It's your decision