Oct 22, 2007

good calories, bad calories

Good Calories, Bad Calories is a book by Gary Taubes. I've linked to a story by him recently and some of you may know him as the author who penned the New York Times piece "What if It's All Been a Big Fat Lie?" in which he arguably started the recent interest in Atkins' low carb diet. One might suspect this new book is in the vein of most diet books or popular journalism on the topic. This couldn't be farther from the truth.

This book is not a particularly exciting read. It's not punchy or written to move copies like a popular diet book. It is rather the culmination of 5 years of research into the existing scientific literature around obesity, dieting, cholesterol, and heart disease. It's hard to know if it is exhaustive but it's certainly more exhaustive than almost anything else I've read on health topics. Think of it more of a "Fast Food Nation" than a "Lose Weight Now!".

It'd be no surprise that Taubes is heavily of the mindset that it is carbohydrates that are making us fat, tired, and susceptible to diabetes and heart disease (and maybe more). And it is certainly hard to come away from this book believing he is wrong. I say this as someone who years ago was of the mindset that carbohydrates were not the key part of the problem. I've done variations on macrobiotic diets at certain points in my life and read a decent amount of literature on them. I was fully in that camp at one point. It was Taubes article in the New York Times that begged me to challenge my beliefs. And believe it or not there are more similarities between macrobiotics and Atkins than there are between those two approaches and the standard, modern "low-fat" diets espoused by a number of governmental health organizations.

There are very few sure things when it comes to health. Epidemiological studies are by their very nature are inconclusive on many levels. And it is these kinds of studies that are used most often when determining if something is healthy for us or not. Taubes reviews many of the studies. He warns both that they are not particularly good ways of determining the truth and amazingly that what has been found is not very accurately conveyed in the recommendations that supposedly are based on these studies. He also nicely delves into the research of many of the physiological processes inside our body relating to fat storage and usage and what drives those processes. It's this section that I find utterly convincing.

At the core, the book makes the case that fat people are not fat because they eat too much or are lazy. As the National Academy of Sciences wrote,
"Most studies comparing normal and overweight people suggest that those who are overweight eat fewer calories than those of normal weight."
That's a remarkable data point. Why isn't this common knowledge? So why can't we lose weight by eating less even though thermodynamically this should work? His claim is that it must be the food and not the individual that is the problem. Something we're eating is making us hungry even when we don't need the energy on a thermodynamic level. We are storing energy rather than expending it. This makes sense on an intuitive level. Animals don't get fat in the wild, even when there is an overabundance of food available. They self regulate without thinking about how much to eat. But animals do get fat on modern 'chow' mixes sold at pet stores. One would expect organisms to have regulatory systems that work in a normal environment. And we are, after all, animals. What is it about the modern diet (our chow) that makes us fat and why when we try standard semi-starvation diets, do the effects not last? A calorie is a calorie from a thermodynamics standpoint. And energy balancing should work (energy in = energy expended + energy stored). We know this. Yet we are getting fatter all the time.

Taubes turns cause and effect around and makes a damning case for it. We're not fat because we eat too much and are sedentary but that we eat too much and are sedentary because we are fat. Or more specifically because we have a metabolic condition that causes energy to be stored as fat and not used for energy we are hungry and without sufficient energy. Eating too much is not the cause. It's a symptom. Fat people really are hungry. Eating less will do nothing for you except make you tired and hungry; your body's response to a metabolic distortion. What causes the metabolic snafu? Carbohydrates and their effect on the storage and usage of fat.

Another interesting aspect of this book is his explanations for why we believe what we believe. If all these studies didn't show what we think they did then why do we believe they did? What are the political and personal failures that led to such erroneous information. It's all clearly laid out.

I would argue most people would not agree with the takeaways from this book. But then I suggest you should be able to read this book and point out the flaws in the thinking. Because I couldn't find any major problems that bring down his primary thesis.

The next book I'll review is intimately tied to what Taubes is saying. More on that later.

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