I'm awfully sorry brneyes but I'm on a UK liquid(ish) diet. Its 3-4 shakes a day but also allowed food. It's not a starvation diet and teaches you to make healthy eating choices. For example: I had a shake for breakfast, another shake for lunch with homemade soup (no bread) and this evening I shall have smoked cod broccoli and cauliflower. And mid evening I shall have another shake for supper.
I don't know the diet you are on, but I do know people who are doing the same diet as me, and just doing 3 days of 4 shakes only to kick start, then shakes with a low carb low fat high protein evening meal.
No one can say how much you will lose in a week, its impossible. My first week (last week) I aimed for 4-5 and had a lovely surprise when I lost 10. But that is just a fleabite in the whole amount I have to lose and I'll not lose 10 in a week again because so much of it was water weight.
The very best of luck to you. Please let me know what you decide and keep in touch