For starters, this had one of the most amazingly on the nose titles I have ever seen associated to a book. I mean, the metaphor goes deep. This book is essentially junk food for the mind, a collection of succulent facts (?) that grab your attention but you quickly forget about as you consume more and more. You know its bad for you, it's wrong, but you just keep going for one more bite, and hey look! another puzzle. I found that the premise did a good job of putting the book above reproach by specifically mentioned the need for skepticism while reading. As a scientist, I personally enjoy being skeptical about claims.
That said, his way of formatting everything into these bite-sized snippets resulted in some pretty poorly constructed explanations. I was personally disturbed when he proposed using logical fallacies to use as arguments in a discussion. The whole point of these things is that they are a sign of a poorly constructed argument! Yes, that might be good advice for messing with a hotheaded teenager, but to anyone who knows anything about logic, you'll just seem like an idiot.
Also, he presented some puzzles that were so poorly formulated as to be inaccurate (or unsolvable), which, as anyone knows, can get very frustrating. Example (spoiler?): one problem involves meeting your mother between your two homes to pass off a dog, and the problem includes the statement "You live an hour's drive apart, at 7:30 a.m you'll both start driving...you want to get back as soon as possible. Should you leave a little earlier or later than 7:30?" and then the answer goes "if you mash the pedal at 5:30, you could make it home by 6:15". What. The. Hell. Why don't I just leave the night before? or take my jetpack. And by what magic did a 2 hour trip turn into a 45 minute road race? The whole point of meeting in the middle was that it wouldn't take more than an hour's drive in the first place. If the aim of this puzzle was to provoke the reader into enumerating all the things that are wrong with it, then I tip my hat to you, sir, it worked.
A lot of his little brain hacks didn't seem to work, either. Chewing while using scissors? really?
After having (almost) finished my BA in psychology, I can safely say to have heard about the great majority of his brain/psych facts (the ones involving references). A good deal were well consolidated pieces of information, but others needed a bit more critical thinking on his part. The self test quizzes started getting on my nerves, essentially since they were nothing more than a horoscope using pop psy terms.
All in all, I thought the premise was interesting, it gave me quite a few conversation starters, but poor execution.