He does say (2:15) that the 2011 study, (the Newcastle Counterpoint Study) showed that Type 2 diabetes could be put into remission.
The research looks at more than just blood glucose levels. A reduction is quickly achieved but it is the restoration of the insulin function to normal levels that defines the study. This is achieved by weight loss.
However, whilst the improved insulin levels can be measured, we have currently no way of telling what the state of the beta cell mass is in so we don't know how stable it is.
The aim of the Mag Res Centre at Newcastle, as far as I understand it, is to develop techniques which will quantify the amount of beta cell damage at the time of diagnosis. At the moment you are either diabetic or non diabetic based purely on a single symptom, blood glucose levels. The reason, damage to the beta cell mass, is not investigated because of the technical difficulties but soon, it should be possible to quantify it in terms of 20%, 25%, 40%, 50%, 60%. The future prognosis will depend on how much damage has been done by the time of diagnosis.
The other aspect of the research is the state of some beta cells. The current approach, that a beta cell is either dead or active is likely not the whole story and it is probable that some are simply metabolically inhibited before they actually die. The study suggests that some of these beta cells can become active again, as evidenced by the increase in insulin production which correlates with the decrease of pancreatic triaglycerides, ie the islets have become unblocked.
But, at the moment, you never know the state of your beta cell mass.