I have read this book, along with Chris Kilham's entries on chocolate (theobroma cacao), and my own ethnobotanical / biochemical studies through many avenues of interest. I always enjoy learning more about the history and culture of this interesting tree. My scientific disposition compels me look at the health sensationalism surrounding chocolate rather skeptically. Of course, these kinds of reviews are rarely popular, but I feel that I do people looking for health a great disservice by not dispensing my knowledge of chocolate, a perspective which merely takes this work into account.
Theobromine - Firstly, chocolate has stimulants (most people erroneously think is has substantial caffeine, which it does not) - chocolate has an analogous alkaloid, called "theobromine" occurring predominantly. It is a strong stimulant alkaloid with an effect on the nervous system, particularly the heart. The cardiotoxicity of this alkaloid has not been established, and I will firstly press for caution here. The effect of this alkaloid may be enhanced by the substantial magnesium content of the chocolate.
Tannins - Raw chocolate is rich in tannins, responsible for the bitterness of the chocolate. Tannin in high concentration can behave as an anti-nutrient, binding up and preventing the absorption of minerals in the digestive system. It also adversely affects the kidneys. Raw chocolate has a very high tannin content, more so than some tannin-rich fruits (such as the skins of jaboticaba), which are recommended to only be eaten in small quantity. Does this rule of potential tannin toxicity not apply to chocolate?
Surplus - Lastly, and partly from having grown cacao trees myself, is the observation that chocolate can be a surplus crop in many areas of the world. Theobroma Cacao bears continuously and prolifically from trees that are surprisingly easy to grow in appropriate climates. Commercially, raw cacao beans are available at bulk wholesale relatively cheap. (Yes, even the organic ones.) Why do we see disproportionately high prices on raw chocolate products? To me, this means the public is paying high retail prices, based on this rather aggressive "health food" marketing we see- a situation which to me suggests a veil of pretense (though perhaps inadvertent) concerning the whole ordeal. Somebody is making a very high profit off this particular commodity. I don't think it is the Cacao farmers / growers. I think a good skeptical pause is warranted.
This book is nontheless rich with interesting information about the chocolate species. What is the point of this review? I have nothing against the authors, whose work I do enjoy. In fact I do eat a raw diet myself, being a tropical fruit grower and researcher. I think the lesson to learn here is we should respect certain foods for what they are, and not worship them for the energy and enthusiasm they impart. This is a key marketing strategy used pervasively nowadays- the idea that whole foods which make you 'feel good' are healthy and 'good for you.' Chocolate fits that bill indeed. Obtaining good health is, in actuality, a subtle endeavor, and "feeling good" is not a reliable or informative gauge for determining a food's overall virtues, or necessarily the state of one's health.
How many foods / substances out there make us feel good, only to burn us out faster? Thus, I stress caution, and encourage all people to research their health interests as much as possible. Hopefully, you see my point.