Probably. Also probably not a good idea to fly solo, without personal medical attention.
Here’s a link to details of the diet, which has reversed some cases of type 2 diabetes, prepared by Professor Roy Taylor. Overall, his advice looks pretty reasonable to me. However, with such severe calorie restriction (600-800 cals/day), I think a multivitamin supplement might be a good idea.
Note that Taylor say any reasonable diet that leads to loss of enough excess weight may be just as good as the Newcastle diet.