@Tannith I agree with Lucy. I believe this is where Professor Taylor's research causes more harm than good. I understand your faith in him as after all, the ND has helped you to come to a good place with your BGs, but please remember that very few actually get a real lasting cure from type 2. Even Professor Taylor can get things wrong, listen to others too.
To diet so hard that you become underweight will affect your health in other ways. It is quite possible that your pancreas has simply aged with the rest of your body and just can't deal with carbs as well as you would like. In other words, T2 was never your fault, it wasn't because you were too fat, it just happened. If you follow a VLcal diet for too long then it's possible that your thyroid will be damaged eventually. Also if you are not reducing carb calories but reducing fat instead then gallstones are a possibility. I know people who have developed both of these problems through harsh dieting.
I am pleased to hear that you won't be following a VLcal diet over Christmas, I was worried you were becoming addicted to dieting. Please consider changing to low carb instead of low cal. Nourish your body and look after it, don't starve it.