They aren't in the book, the general one most of us have, its only with coaching i think that they are mentioned, but we have all read about them here and there.
You can only have two a day, and if you find you don't lose or you gain the next day then don't have that tolerated, trial and error.
For me i can't have normal soy sauce (I must make sure its sodium reduced), and cornflour even in its smallist amounts stops me losing the next day.
If you need more info try googling it. theres a lot of other websites where individuals have put it on their own blogs etc.