The now oft heard statement that you can 'reverse your diabetes' is a bit of a misnomer.
What is possible 'for sufficiently motivated individuals', to use Taylor's words, is that the so called inevitable progression of the disease can be stopped. This is apparantly due to the discovery that the insulin beta cells are not either dead or alive as previously thought, but that some appear to 'metabolically inhibited'. If you lose enough weight, for many, but not all, these beta cells can start producing insulin again. However, the ones that are well and truely dead remain dead. This means that you have to remain vigilant because your insulin production can decline again if you don't take care of yourself.
The old idea that if you became diabetic that even if you controlled it by losing weight and lowering your fasting glucose levels, that control would become increasingly difficult to maintain and the disease would then inevitably progress was due to a study known as the Belfast Study and as Taylor summarises it, this 'study provides an example of moderate weight loss leading to reasonably controlled, yet persistent diabetes. This study showed that a mean weight loss of 11 kg decreased fasting blood glucose levels from 10.4 to 7.0 mmol/L but that this abnormal level presaged the all-too-familiar deterioration of control'.
Taylor's work had led him to the following conclusion: "The extent of weight loss required to reverse type 2 diabetes is much greater than conventionally advised. A clear distinction must be made between weight loss that improves glucose control but leaves blood glucose levels abnormal and weight loss of sufficient degree to normalize pancreatic function." As I wrote above, it is the progression that is being halted, not the disease. It can return.
If you have had diabetes once, you can get it a second time easier than you got it the first time. The good news is that it does not need to be progressive. Just don't push things too far.