Sunday, July 27, 2008

Double book review: Good Calories, Bad Calories and In Defense of Food

Recently I read two books in succession that share the same basic theme: the modern Western diet makes people sick.

Gary Taubes' Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease (****) offers two main assertions (along with several more secondary ones): 1) the hypothesis that dietary fat makes people obese and sick is false, and 2) carbohydrates make people obese and sick.

Surprisingly, considering how stridently the idea has been preached for the past 30 years and how deeply it has penetrated our conventional wisdom, Taubes succeeds in utterly demolishing the soundness of the dietary fat hypothesis. He demonstrates convincingly that the science underlying it has always been extremely shaky, based more on suppositions and assumptions than anything else, and promoted by people who habitually dismissed or misinterpreted contrary evidence. Indeed, Taubes deliberately refuses to call the people behind the hypothesis's popularity "scientists," because, he says,

It's... debatable, at best, whether what these individuals have practiced for the last fifty years, and whether the culture they have created as a result, can reasonably be described as science, as most working scientists or philosophers of science would typically characterize it.

Taubes is less successful at proving his second point, that carbs are the root of all dietary evil. He certainly demonstrates that the evidence is suggestive, but essentially he is guilty of what he justly criticizes the nutrition "scientists" for doing: he reaches conclusions on incomplete evidence and then asserts their truth without waiting for confirmation through proper research. Of his 15 "inescapable" conclusions, the only one that seems convincingly proved to me, at least as presented in the book, is the lack of support for the dietary fat hypothesis.

From a reader's perspective, Good Calories, Bad Calories is heavy going. It's not easy to read. It's rather long-winded, technical, and repetitive. But it's difficult to overstate how important this book is. It demonstrates convincingly that one of the most important things we thought we knew about food -- fat is bad for you -- might well be nonsense. And it compiles provocative evidence suggesting that many other things we think we know -- including even the basic idea that people gain or lose weight depending on their "caloric balance" -- may be equally wrong.

In contrast, Michael Pollan's In Defense of Food: An Eater's Manifesto (***), is less polemic, more balanced, and easier to read. Rather than a list of 15 bullet points, Pollan's advice can be summed up in three short phrases: "Eat food. Not too much. Mostly plants."

"Eat food" means "Eat food that our ancestors would have recognized as such." Pollan contrasts "food" with the "edible foodlike substances" produced by nutrition science. Where our dietary advice has gone astray, he argues, is in the rise of "nutritionism," the idea that nutrients, not food, are what matters. Since we can't recognize nutrients on our own, a vast system of expert nutrition science and nutrient marketing has arisen, a "nutritional-industrial complex," if you will.

Unfortunately (as Taubes also argues), the "experts" often don't know what they're talking about. But unlike Taubes, Pollan argues that where they've gone astray is not in promoting the wrong nutrients (e.g., carbs over fat), but in reducing food to the sum of its nutrients in the first place. Our bodies evolved to consume food, Pollan argues, not nutrients, and failure to obtain food makes us fat and sick.

So Pollan describes the rise of nutritionism and the rise of the Western diet, and then tells us how to escape and change our diet. His advice is common sense: eat better food, eat less, and emphasize plants. The result, he argues, is that you will be healthier and enjoy your food more. It's hard to argue with that. The only real difficulty with his advice is that "food" tends to be significantly more expensive than "edible foodlike substances." But then, poor health is even more expensive.

1 comment:

  1. I also recently read In Defense of Food. After having worked for a decade in the "food and beverage industry" as a process engineer, I believe Pollan to be correct about the nutrition science. It's not designed to keep people healthy or even nourished, it's designed for maximum profit at minimum expense.

    Our food bill has increased a lot and cooking time is quadruple what it used to be, but I believe we're healthier and working toward better long-term happiness as a result.

    FWIW, The Omnivore's Dilemma also by Pollan is one of the most thought-provoking books I've ever read.

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