Jennifer Aniston is apparently on the Aitkins diet like the one you describe - skinny as a rake...its working for her, but one must make sure low-carb vege intake is there for other minerals etc...
I just wanted to add that most celebrities and famous personalities should not be used as examples of health or lifestyle living. I read a lot of interviews with famous people, and I find it interesting that the majority of women who are regarded as "beautiful" -- are smoking during the interview. Yup, Ms. Aniston was one of the ones puffing on a cigarette while taking inquiries.
I have nothing against these people at all, I'm just saying I don't think it's a very good idea to look up to them as examples of what does or doesn't work as far as diet and lifestyle.
Most are smoking (as a substitute for actually eating), starving, vomiting, taking steroids, or having surgery because, unfortunately, their profession demands that in order to keep working, they HAVE to stay thin -- no matter what the risk or cost. (Jane Fonda and other "fitness gurus" come to mind.)