what i'm reading: rethinking thin

I just finished Rethinking Thin: The New Science of Weight Loss - and the Myths and Realities of Dieting, by Gina Kolata, who is a science writer for the New York Times.

The book is framed around a university-sponsored weight loss study, a highly controlled and supported experiment to see which of two diets results in more weight loss. Around this framework, Kolata takes you through the history of the diet and weight loss industry (it's much older than I thought!), and an examination of the available scientific evidence about weight loss.

Kolata's examination of the data brings her to these conclusions:

  • Humans have very little control over their weight. Your weight is about 80% genetically determined. You can affect your weight only within a small range.

  • Being overweight is not a serious health risk. Other than the morbidly obese, being fat in itself has very little effect on your health. In fact, being what society considers slightly overweight appears to extend life span and promote good health. (Note that this is a separate issue from exercising and eating healthfully. You can do both and still be overweight.)

  • No diet works better than any other diet. As every chronic dieter knows, you can lose some weight on almost any diet, and you will always gain it back, and then some. This is not merely observational and anecdotal. It is fact.

  • People are becoming fatter, but it's not their fault, and may not even be bad, except, of course, socially. An analogy can be drawn to height. In the last century, people in first-world countries have become taller. This is not because humans have changed genetically, but because, for the first time in history, changes in medicine and nutrition has enabled humans to fulfill their genetic potential for height. According to the data, the same goes for weight. It appears that humans have an enormous potential to store fat, and only now, as a large segment of the population has access to unlimited nutrition, are we seeing that.

  • Data that supports the above conclusion - no matter how rigorous the study, no matter how clear the evidence - are attacked, ignored or dismissed. Studies that support socially acceptable conclusions - no matter how flawed the study or flimsy the evidence - are promoted. This is a running theme of Rethinking Thin, and alone makes the book worth reading, for the general comment on the uses of science in society.

    When I wrote about eating disorders, experts were beginning to see data that supported these ideas. I waited for the news to filter down to the general public - and kept waiting. It never happened. Rethinking Thin explains why.

    It's a short book and easy to read. Some of the science was a bit beyond me, but that was a minor part, and didn't affect my overall understanding.

    The conclusions of Rethinking Thin are certainly controversial. But before anyone dismisses them as hocus-pocus, I would read this.
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