Hi Holly and Bravebb, welcome to the site. Hope you find support with each other. To answer your questions holly, yes it is okay to do this diet, giving up starchy carbs can only be a good thing and the calories and low carbs are key to the good weight loss. Anyone will put weight back on if they go back to what they were doing to make them overweight in the first place. If you can get to your goal weight the sensible thing to do is join the Maintaining thread (search engine) and I believe they add say 50 cals after one week so on 850 then another 50 to 900 and so on. A good way to look at this is that it is a way of life but you will hopefully reach a point where you dont have to be quite so strict and can go onto the 5:2 or the Med diet. But do give the full 8 weeks a go. Finally, our results. Well you can ask a dozen people and you will get 12 different answers. I only had (ONLY!!!) 3 stone to lose and lost 1 stone in the 8 weeks, some people who are bigger at the start have lost 2 or 3 stones. Dont try to measure yourself against anyone else, we are all different.
Bravebb, this is a good place to start getting your bloodsugar and cholesterol down. It looks as though you have a plan so good luck but do be careful with the ready made shakes as many are high in sugar and carbs so read labels carefully. One shake I have used but not seen for years is Complan which was designed to rebuild strength in people who had been ill. Alternatively you can make your own using a machine with things like spinach, berries, nuts and seeds.
Good luck to you both and Keep On Keeping On……