Not to sound like a skeptic, but to me, this kind of thing is a reminder of how much we really don't know - even in areas that we tend to assume modern science has pretty well figured out.
This is especially irritating in the "how to be an epicurean" genre of books when they get into specific, supposedly scientific, lifestyle advice, psychology, etc.
Reminds me of an anecdote about reading a news article about the field you work in, and thinking, "That is so misleading! Lots of people disagree about that. That's not even what the paper said! The paper they're referencing was retracted 6 months ago!" Then you read an article about a subject with which you're less familiar, and you don't realize it may well have all the same issues.
Now back to being dogmatic.