I enjoyed it, though the middle section could have been condensed a lot. It's by a bariatric surgeon who realized that what he had been taught in med school was inconsistent with the experience of hundreds of patients he had treated. Conflict between received theory and observation frequently prompts excellent research and I think it does here. While I don't think much of what he has to say is novel, he has used other pieces of theory to explain his observations. And it's very well written.
And see also "Groundbreaking New Intermittent Fasting Study". (15 minute video.)