2/10
No effort was put forth in this book. Its not that it was bad, but that it was essentially intentionally so. I can't help but think that the author might literally not have read the book of Daniel, from which the title, and not much else of this book, is derived. I feel this must be the case, as somehow, Gregory did not realize that the story in Daniel, and the diet therein, is specifically mentioned because of its incongruity to the original audience. To the audience, anyone would expect a diet of meats, grains and wine to be super to one of vegetables and water. In the Biblical text, it is clear that this is a divine act, showing Gods favor for Daniel, rather then Gods favorite diet.
Even if this was not the case however, this is still a terribly written book, that combines pseudo self help theology with terrible diet advice. The only reason it isn't one star is that yes, it is generally good advice to eat more vegetables. In this regard, you would be better off listening to Michael Pollan, who gives the admittedly non-shocking advice of "Eat food, not too much, mostly plants." I would add one thing to this list If I could, "and avoid reading the Daniel Cure".