The only problem with this explanation is that most type 2 in the first few decades actually have higher than normal insulin levels, proving the beta cells are still pretty darn active. Eventually they can “give up” but this happens much later in the progression of the disease.
That said significant weight loss definitely helps some type 2 in quite drastic ways, I’m just not convinced that reawakened dormant beta cells are the mechanism by which it works.
Certainly the very low calories his methods use also automatically mean low carbs (low everything in fact) so perhaps it’s as much that as other factors. Or allows better regulation of glucose dumping from the liver once the fat around that is reduced. Or maybe the missing first stage insulin response is reenabled by the lack of fat around the pancreas.
Excess fat is as much a symptom of metabolic dysfunction and insulin resistance leading to type 2 as a cause of it. Chicken and egg.
I use Gliclazide medication. Initially, I was on max dose and it hardly did anything for me, so my GP wanted me on insulin. I went Low Carb instead, and very soon as my weight dropped, my Gliclazide doses had to be cut drastically since they suddenly started working. I dropped from 320 mg/day down to 40mg/day, and dropped my Metformin from 2000mg to 500 mg
What is interesting about Gliclazide is that it only works when there is a demand for insulin, and then it squeeze more out of the Beta cells as a booster. If I take my Glic after the meal, it has no effect. So, this is evidence of the sort that my Stage 1 insulin response was also restored by my change in diet. I then had to do a blue light jobbie to the hospital, and those nice A&E doctors stopped all my meds -cold turkey. Then I went on hospital food. BUT, I did not have my sugars jump up into the chandelier, but there was a response that approached 'normal'. I found that after a while I was actually able to eat carby meals and not spike. I was in Remission, which the hospital consultant confirmed. On my birthday on the ward, I had cakes, choc fudge, and Danish Pastries, and survived with a bgl of about 12, which was amazing.
Then I had an operation, and the anaesthetic pushed me back into diabetes land again, which is where I am still. I am medium carb now, not LC , and my HbA1c is non-diabetic, but I do get spikes.
So I am convinced that I (a) recovered my insulin output, (b) restored in part at least my Stage 1 Insulin Response, and (c) can survive without medication if I need to. I did it the LCHF (non-keto) way rather than low calorie, but as has been pointed out, it becomes a technicality since there comes a point where they both seem to merge anyway. I did not lose much weight though so that was not the requisite for my recovery. Losing fat from around the midriff was the probable panacea.