The book is a thinly disguised vegan manifesto.
It's extremely disingenuous and misleading in that it promises to teach you how to lose weight without going on a diet while eating foods you like but then it tells you that you have to "rewire" your brain to learn to like the "right foods", essentially making the initial promise sound like like a bold-faced lie.
But that wouldn't be too bad in and of itself, unfortunately, the author makes a bunch of crazy-ass claims about apes and humans and whatnot that are simply not true, like he claims that apes only eat plant based foods but it's a well established scien-fucking-tific fact that chips, the closest apes to humans genetically, will often kill and eat other mammals and primates. So either the author is ignorant or he deliberately lies in the book.
His claims about human anatomy also fail to stand up to scrutiny.
And while making all those claims, he never once cites a single study, he just presents them as "folk wisdom".
In other words, the book is bullshit.
But then again, vegetarianism is a valid dietary choice, so the fact that it's peddled by hacks like this book's author shouldn't detract you from giving it a try.