It's more about the eating advice than the 800 cal part of it. I still can't understand why I've been told to eat carbs, carbs and carbs in the handy leaflet I got given to explain my diabetes to me.
I've also been looking at just low carbing and keto type plans too. For me the 800 cals is working well but the low carb aspect is the most important bit of it. Also the diet is not meant to be done forever - as you say it wouldn't be sustainable.
For me though, the thought of the worst part of diabetes means that the diet made a lot more sense to me than being stuck on tablets which (as I understand it from 'The Obesity Code' by Dr Jason Fung who actually started the Intensive Dietary Management centre) is like trying to put out a fire by pouring petrol onto the flames.
Hi catapillar, no, this type of diet has been around for decades, even centuries along with fasting and other things that we western world (mostly) people do. 'The Obesity code' cites loads of research that has been 'lost' or overlooked due to the food industry wanting to push a load of **** down our collective throats and keeping us sick. Then of course we have big pharma in whose interests it doesn't make sense to have a load of healthy people who don't need to buy their drugs. I firmly believe that this is why we have such resistance to these old (new) ideas.
The rapid weight loss that the blood sugar diet gives is part of its charm, especially for entrenched carb addicts

Although for anyone who is curious about the affect it is having on people's lives then the forum/site is also free to register to and has a really supportive community who are very happy to answer questions. We have a mix on there of type 2 and non diabetic people.