It's surprising how fast IF is becoming big news over here. There was another double-page spread in The Mirror tonight.
Meat is Prized, Wheat is Despised.
Real Food - The REAL staff of life
From the article, it appears that although participants were allowed to eat 'whatever the hell' they wanted to the rest of the time, they did not go crazy, and ate normally.
Maybe the very idea that you COULD keeps you from doing it.