Do you agree all these points?
Caloric Restriction - I've done that and lost 1/3 of my body weight, admittedly there was a lot to begin with and I could do with losing the same again. Problem being that severe calorie restriction has taken it's toll (possibly) because my metabolism is quite happy to survive on meager rations. I've had my insulin resistance measured (possibly calculated, I can't tell) and it's gone from 1.7 to 2.4 and back to 1.7. I also think that reducing calories by 25% or even 12.5 % as mentioned in Research Design and Methods would probably mean a similar reduction in carbs. If somebody could translate the results into English I'd be very grateful.
Nutrition Changes - It hasn't affected my insulin resistance but maybe I'm an isolated case. The changes I have made, no processed food, bread, pasta, rice or potato have improved my health, but as noted my insulin resistance has actually gone up and back down again.
Exercise - There was a six month period in my life where I did a lot of exercise recently, since I was diagnosed, 5 X (500m - 1,000m) swimming, 3 X 1hr gym, 1 hr personal trainer and a round of golf. My diabetes showed no signs of improving (IR not being measured in that period). In fact it as around that time I was discussing going onto to insulin but started low carb instead.
Vitamin D - I take 250μg because I know I have a deficiency. No change noted.
Probiotics - Take those as well, again I had my gut bacteria investigated and knew there was a problem. No change in IR noted.
So, my personal experience would make me say I don't agree. Based on the fact that everyone is so different I don't know.