[Gatsky]

This is an issue with any pop-X book, namely that complicated, messy topics are oversimplified and packaged neatly.

As a reader, it is very enticing - you feel like you are learning very efficiently, the reviews are filled with comments like 'I learned more from this book than 5 years of geography/economics/history/physics/chemistry etc in school'. People that have swallowed the pop-X book wholesale become evangelists, telling everyone who will listen how important it is to 'Sleep for 8.5 hours a night', or 'Stop eating bread'. But really, you are often paying to be told a fairytale about topic X.

[yaseer]

I agree with your points, but I wouldn't group the importance of sleep with diet fads.

There's an overwhelming amount of non-contradictory scientific evidence on the importance of sleep.