Good Calories, Bad Calories

If you read this blog chances are you have spoken to me in the last two months, and if you've spoken to me in the last two months chances are I've mentioned Good Calories, Bad Calories by Gary Taubes. The book's main contention can be glibly summarised as thus:

• saturated fat isn't bad for you;  
• sugars and refined carbohydrates are bad for you;
  
• inactivity and overeating are no more the causes of obesity than overeating and inactivity are the cause of weight gain during pregnancy. They're the symptoms; and
  
• diet + exercise does not necessarily equal weight loss.

There is a terrific summary of the current knowledge in the epilogue of the book, but to recite it all here would be an injustice to an enormous book, filled with intelligent and insightful commentary on 100 years of nutritional research. The first half of the book is almost dedicated to debunking the myth that dietary fat has been proven to be the cause of heart disease. If you're interested in reading summaries of study after study failing to show a causal link, or even a strong correlation between the two then you'll be riveted by it (like I was!).

The last point listed there is, however, probably the most profound in the book. Taubes argues that 50 years of nutritional and obesity prevention information have suggested that decreasing one's calorie intake and increasing energy expenditure will lead to long term weight loss. In short, most evidence suggests otherwise, rather it suggests that decreasing your calorie intake and increasing forced calorie expenditure leads to a decreased metabolic rate and hunger. Hunger is a very significant aspect of the book too, Taubes makes it very clear that hunger is a natural signal to your body to eat. Persistent hunger is not a psychological problem, it's a physiological signal that your body is not getting the energy it requires. I summarised it to someone as thus:

• Humans get hungry when their cells need energy.
• Humans are most healthy and thus, probably evolutionarily designed to be lean.
• Therefore, if you're overweight and hungry you're doing something wrong. You don't need to harden up or learn to be hungry (there are horrible psychological affects of continued hunger), you need your body to stop storing energy and start processing it.

I believe that is a fair, if succinct, summary of the specific dietary findings of the book. If you're interested in changing the way you eat or avoiding one of the diseases of civilisation then I highly recommend you find a copy.

However, the book is so much more than a summary of nutritional and obesity research. As it details 100 years of research it is also a commentary on the progress of health science, controlled and observational medical research and public health policy. It appears that many researchers in the field disregarded good scientific practice by never questioning the findings of their predecessors; officials who believed they needed to give some kind of advice preached 'proofs' that were anything but; and finally researchers in different fields failed to communicate their findings between one another.

Don't fear though, it's not at all a diatribe and nor is it a book requiring faith in Taube's findings. He makes it quite clear when the science has failed to conclusively prove anything; and if you so desire there are 114 pages of notes and references to review. Finally though, don't take my word for it, take the word of someone who makes a living out of being sceptical.

Gary Taubes uses an impressive combination of rigorous logic and no-nonsense empiricism to thwart medical dogmas, particularly the one about the 'calorie-in, calorie-out' notion that no evidence can dislodge from the mind of medical doctors. This is a true document about scientific method, even a monument in the history of medicine - and something that will change your life.
-Nassim Nicholas Taleb (author of The Black Swan)