Natalie, the cabbage diet is one of the ones used by some people in hollywood to "make the dress size" for awards shows and whatnot. These people will basically kill themselves for a couple of weeks to drop some pounds to look great on the red carpet. It is a little wierd.
The diet is here:
http://www.cabbage-soup-diet.com/
Sadly, Hollywood is seemingly locked in another round of waif-thin girls, I think started this time by Paris Hilton (who is naturally tall and thin, plus what the doctors gave her, I guess)... you see girls like Lindsay Lohan or even Nicole Ritchie, they are borderline scary in how thin they have become. Hopefully the girls of the world are not taking this to heart, it is really sad.
Alex