Because Dr. Schwarcz is a chemist, he focuses on the actual chemical substances that have effects within our bodies. The book is divided into four parts. The first and longest part deals with natural substances found in the foods we eat. The second part deals with artificial substances and genetic modifications. The third part deals with contaminants. And the fourth and shortest part—surprising, given the title—attacks spurious health and nutrition claims.
The chapters are very short, most of them only three or four pages long, and each one is written to stand alone, which leads to a lot of repetition of basic concepts and key facts. This is both annoying and effective since it reinforces ideas like the fact that we needn't worry about carcinogens in our coffee since they're in such small amounts and, besides, there are carcinogens in practically everything we eat. Over and over, Schwarcz hammers home several important points.
Eat your fruits and vegetables, for starters. He discusses specific nutrients and beneficial chemicals (lycopene, anthocyanins, carotenoids) they contain that are best ingested along with the hundreds of other chemicals the foods contain. Whole grains are also good, as are some spices like turmeric and cinnamon. Time and time again, he pooh-poohs the general practice of simply taking supplements, citing studies that showed that the supplements provided no benefit. Well, sometimes. Sometimes the supplements are beneficial in specific populations—usually in patients with a condition to begin with, not healthy patients seeking preventive medicine. Vitamin D supplements, though, are ones he recommends, since the recommended daily dose of vitamin D is much higher than one would get from diet alone.
Schwarcz backs up his recommendations with science. Although he provides interesting anecdotal data, he always follows it up with data from trials and interprets the results for the reader. He points out numerous times that claims of a substance's benefit or harm are frequently made based on results in animal trials. And in these trials, the animals are often given doses hundreds or even thousands greater than are actually found in the foods themselves, making the claims relatively meaningless. For instance, in one study, rats were fed an artificial sweetener, and they developed bladder cancer. The amount they got, however, was equivalent to a human drinking 350 diet sodas a day. He examines the amounts of various substances found in foods and compares which are better sources of vitamins and nutrients. He also points out that you only get the benefit of these nutrients if you make them a regular part of your diet. Eating an apple once every couple weeks isn't the same as eating one a day.
Dr. Schwarcz clearly has it out for self-proclaimed health gurus with questionable degrees and calls out several by name to debunk their crazy claims. He also rebukes several activist groups who crusade against foods with one substance of questionable health risk among dozens of other substances with proven health benefits. As he says frequently, there are natural "toxins" and pesticides in the fruits and vegetables we eat already, and no one seems to get up in arms about those. He does acknowledge when the issues are hazy, however. Even though he's obviously biased toward scientists and their fancy "clinical trials" and "evidence" and "data," he notes when the activists do actually have some science on their side.
The tone is somewhat lighthearted, but not consistently. Schwarcz's attempts at humor or a cute punchline frequently fall flat or seem out of place or non sequitur. That said, it's extremely readable, and he doesn't let the text get bogged down in polysyllabic words and confusing biochemistry, focusing on the high-level concepts. The chapters are of varying quality; some seemed very superficial and didn't address issues I expected to read about. I also felt that, since the chapters were meant to stand alone, there wasn't a consistent sense of structure or organization throughout.
Overall, however, it's a very good overview of the things we put in our bodies and what they do to us, what we can do to stay healthier, and what we really don't need to be worried about, sensationalistic headlines be damned. I learned a lot, and I was especially interested to read about the results of all the trials. We rarely hear about food-related trials and what the results actually mean, only what the media spews out. Even more interesting were the studies of trials, searching the aggregate data for potential health benefits or safety risks. But besides all that, you've got to love all the food history trivia! Like did you know that spinach actually has very low iron content, and the reason the creator of Popeye believed spinach was high in iron was because in the eighteen hundreds, researchers screwed up a decimal and the result was propagated for decades? And that pretty much all artificial sweeteners were discovered by accident? And that the word "canola" comes from a combination of Canada, oil, and low acid?
I haven't read any other books on nutrition, so I don't know how this one compares. I thought it was pretty good, but not as amazing and enlightening as I was hoping for from the title. It did make me think more about what I eat. Even though I obviously knew I should eat more fruits and vegetables and oats and fish and whatnot, it really helps to know why, specifically. Now I know what actual health benefits I can reap from diversifying my diet!