Hi @exchoc
Am I right that you would be aiming at two different things? 'Reversal' and weight loss from the tummy area?
Because 'reversal' is something that can only happen if a number of circumstances align - these include having enough insulin production left to cope with our ongoing carb intake, having a pancreas and liver that are not fatty any more, and continuing an eating regime that does not overload that capacity.
When Professor Taylor began the Newcastle Diet studies, he quickly learned (1st study) and confirmed (2nd study) that the longer a T2 has been diagnosed, and the longer they have had a fatty liver, then the less likely they will experience 'reversal'. Yes, they may well lose significant amounts of weight, and yes, their blood glucose control may improve. But actual 'reversal' according to the study criteria? That became less likely, the longer the diagnosis. I believe that 4 years and under produced the best 'reversal' stats, with decreasing chance of 'reversal' as the length of diabetes increased. Although some participants did 'reverse' after significant numbers of years, so it is always possible!
So your 12 years of T2 may place you at a bit of a disadvantage. Please understand, I am not saying this to put you off trying, just to suggest that you temper your expectations, so that you don't feel crashingly disappointed if you don't achieve 'reversal'.
My second point is that there is a big difference between subcutaneous fat and visceral fat. Visceral fat (fat in and around the organs such as the pancreas, liver, kidneys and heart) is more important to our health than subcutaneous fat (fat under the skin). This is why being Thin Outside, Fat Inside (TOFI) is such a health risk.
If you lose weight overall, then you will lose both types of fat, but I am not sure that there is any calculation that you can do to anticipate how much apple shape fat you would need to lose to achieve the necessary visceral fat loss, and we are all different in the amount of visceral fat we require to impair our glucose regulation.
And finally, I am not aware of any studies or findings proving that these rapid crash diets are any more effective at 'reversing' than a slower low carb weight loss way of eating. Yes, you get the results a bit faster, but there are plenty of studies around now showing that low carb is just as effective at de-fattifying the liver as other, more extreme calorie restriction diets.
I would be very wary of any diet regime that required a £99 up front fee, but then I am aware of how easy it is to source excellent low carb blood glucose controlling information on the internet. Mind you, I can see that the mindset of 'I paid a fortune for this! So I am bloomin' well going to get my money's worth!' might be a motivational tool.