This is actually the book I had to read to get credit for my high school gym class (I did not have to do any of the actual physical requirements for reasons obvious to those who know me personally). It's been a while since I've read the book, so this post will be relatively short.
It's an entertaining read, to be sure, and while I agree with the general guidelines given by the book, I believe that due to the current state of humanity (that is, we have far more people to feed than we did before processed foods came along, so food has to be cheap (and, as it stands now, not necessarily healthy) to maintain the current world population level), implementing many of Pollan's proposals can only be done by the wealthy (i.e. those who can afford to buy organic produce and the like). Also, several studies have shown that organic food is no healthier for one than conventional produce. It seems like what matters more is eating home-cooked food instead of processed/packaged food. Bill Clinton has lamented how in India, people have switched from eating the delicious (in my opinion) traditional meals to eating fast foods like McDonald's and the like, and that this is a major contributor to the rise of obesity and heart issues in India. (I will add that some of these problems already existed in India prior to the advent of multinational fast foods, owing instead to the over-reliance on refined rice as the primary energy-packed food.)
But more than that, I feel uncomfortable with Pollan's outright rejection of nutrition science, especially since analysis of vitamins in food has led to the eradication of many diseases caused by lack of vitamins. While it is true that incomplete science should not be used as a basis for prescribing diets (see, for example, the warnings against saturated fats leading to the prevalence of trans fats (due to overuse of partially hydrogenated oils)), neither should the incompleteness of the science mean by itself that the science should not be pursued further. I feel like Pollan is blinded by his own zeal; where he means to say that dietitians should not enthusiastically convey new studies' recommendations especially when the studies are very focused [on just one aspect of a certain food type], he instead essentially says that the studies themselves should not be carried out at all.
