Beta cell function declines in T2DM. The prevailing theory is that they simply burn out after years of overproduction due to insulin resistance of cells. Unless this diet can regrow beta cells the article is complete garbage.
Actually, the body can regenerate beta cells.
Autopsies of type ones have found a lot of dead beta cells well out-side of the Islet of Langerhans.
I wonder with T2 if the Beta cells actually die or if they just go into hibernation.
I know that hormone-producing cells can become 'exhausted' and be brought back with a rest. "Adrenal fatigue" is one such example.