I did the blood sugar diet when I was diagnosed, which is lowish carb, 800 calories a day for 8 weeks. Then 5:2 thereafter for a month. The 1st 8 weeks were hard work for both me & everyone around me. Would not recommend unless you are extremely overweight.
Having said this I went into remission & have not gone back into diabetic range in 2 years. So it worked I guess
Now, I follow low carb all the time. I also try to do intermittent fasting a few times a week which sort of ends up being a 5 2 albeit unintentionally. The easiest way to do this is to skip breakfast. I just don't eat until lunch & keep everything else the same. I eat quite alot of green veg, a small amount of berries & then protein, full fat dairy, good fats (nuts, seeds, butter, olive oil, olives) every day.
On a fast day I try to avoid too much cheese as its my downfall. Otherwise I eat 2 meals like normal.