It's a possibility that you won't be allowed to do the diet, but that isn't cast in stone. As I understand it, you'd need to have your GP's agreement to do the diet, in otherwords, he/she will have to sign the medical form.
To some extent, I guess it'll depend on what your depression's about. If any of it's to do with how you feel about yourself at your current weight, then losing some, and losing it fast would help. But CD needs quite a strong mindset, and finding yourself unable to stick to CD might make you feel worse.
It's a tricky one, and to a large extent depends on how your GP views VLCDs. Some can be quite adamant that reduced calorie diets and exercise are the only way to go--but as many of us here can testify, that's often easier said than done.
Talk to your CDC (who will almost certainly tell you to talk to your GP) and discuss your options. I think the lowest CD plan you can do without permission from the doctor is 1200.
Hope you get something sorted hun. :hug99: