If you know nothing about digestion or nutrition, want an easy-to-read, concise overview, and find you struggle a bit with books on the topic of science, this is probably the book for you. For the price it seems reasonable, and can be read in a single session without breaking much of a sweat.
If you've read any other books on the subject, you'll likely find this too lightweight and of little value. There was the occasional fact that was new to me, but I found the other reviewers opinion that it's much like a pamphlet from your doctor's surgery to be quite accurate.
Other, more detailed books like
Digestive Wellness are quoted in the pages here, and it made me think I'd have been better off buying those books instead and getting the original account in full detail.