Oh dear. What dreadful things to tell you..
Honestly what on earth can that sort of thinking be doing to patients?
Seriously - diabetes is an inability to deal with carbohydrates. They are the sugars and starches and a modern diet is crammed with them. They are considered healthy.
An ordinary type 2 diabetic can usually find themselves feeling so much better quite quickly. Usually type 2 sneaks up so people adapt, or think that it is normal to feel old and decrepit.
Cutting out the dense carby foods takes such a load off the metabolism.
I've been told to take less Thyroxine as my thyroid is picking up, after a very long time of taking 200 micrograms a day, I am now on 125. Thyroids are not supposed to do that, or at least I have never been told that there was any possibility of recovery.
These days I enjoy meat, fish, cheese, eggs and I have salads, stir fries and other veges, mushrooms, berries and a few other low carb fruits, but I find that my appetite is very small and I have no need to struggle to keep to the diet.