I'm coming in here to answer
@rab5 question literally.
The reason why carbs are advised to be eaten by T2s is because, usually unless you're in ketosis and you get your energy from ketones,
you need carbs to give you the glucose sufficient to provide the energy for your brain to work as a normal healthy person would need. The belief that carbs are necessary for your nutritional needs in vitamins and minerals. Also fibre. So a healthy balanced diet of carbs, (preferably low GI or complex), protein and healthy fats! In other words the eat well plate!
This does work for those who can tolerate that amount of carbs.
The problem starts when tolerance levels to certain foods exacerbate your blood glucose levels. A steady diet of too many carbs will of course, be unhealthy for you.
It is this tolerance of food that you are trying to discover to lower your carbs intake sufficiently to improve your hba1c levels.
For T2s, the level of tolerance, for example potatoes is important because some can and some have to avoid them completely.
That depends on your first insulin response, your insulin resistance, your circulating insulin levels.
This is why the medical profession promotes carbs. Because of the glucose levels derived from carbs.
This forum advocates a reduction in carbs, higher levels of natural fats and proteins to find the right balance for you.
This can only be done by monitoring blood glucose levels.
My last point is sustainability of being in ketosis for a long time.
As I did when I lost a lot of weight and my health dramatically improved, my endocrinologist tried to encourage me to raise my blood glucose levels above normal levels. So I would get the health benefits of not being in ketosis. But I'm weird, and would not work.
Being in ketosis now for four years, and my body likes where it is, I am intolerant to carbs, so I avoid them. I have that option.
I also do intermittent fasting, eat small meals and have not eaten a potato for about seven years, because they are so bad for me. But my wife will still eat one jacket potato and it doesn't spike her!
I know my body because of my experience with testing and my food diary, I eat to my meter, my wife can and does eat carbs, because she can. I cannot and would not advise anyone to go into ketosis unless it is apparent that they need to because of the condition they have been diagnosed or the symptoms they are showing.
Best wishes.