Why Calories Count: From Science to Politics

People should read this book. They should read it if they are obsessive weight-watchers or serial dieters, or just concerned about what their children eat. They should read it if they work in public health, the food industry, catering or education. And they should certainly read it if, like my colleague who reacted with horror to the title and the idea, they work to counter the "myth of obesity" and are supporters of the "health at any size" movement.

Why? First, because it lays out the contradictions and historical contexts of the confusing definitions and measurements involved in "calories" and explains clearly why it is an elusive concept. Second, it shows the politics of the contemporary food system and exposes the weakness of "labelling" as a tool for understanding what we are eating. Food environments are shaped by those with profits to protect and power to maintain; big business is not philanthropic when it comes to feeding people reasonably and well. Third, by laying out the science and complexities of the system and by making power and profit transparent, the book aims to enable the non-specialist to know what is being done to their food and how to choose it well. Its premise is that we need to be able to read labels intelligently: to know what is behind deceptively simple charts and numbers, and to make quick sense for everyday practice. It concludes with advice on managing dietary intakes so as to eat better: healthily and with pleasure, and to help lose - and not regain - weight.

Written by two highly acclaimed professors of nutrition and, in Marion Nestle's case, also of sociology, Why Calories Count lays bare how the US food industry engages with the regulatory institutions to ensure that labels and messages about health suit industry ends rather than consumer clarity. They argue that contemporary shopping habits and eating out work against people trying to eat merely sufficiently; it is hard to avoid excess. This is partly because calories are invisible and tasteless, so almost everyone underestimates the energy content of the simplest, most familiar foods and meals - including nutritionists, as they show. We all need to tool up, and this book tries to show how.

I have some complaints: the print is small and the text dense, so more diagrams, boxes and easily understood figures would have helped. The authors write with style and pace, so the scientific sections are comprehensive but reasonably readable, but I wonder how far into the information the "ordinary shopper" would actually get. You have to reach the book's concluding section to find direct and clear advice. More seriously, it ignores the politics of the thinness industry - the pharmaceutical companies that are linked to the dieting industry, and the nonsense of "lite" and "sugar-free" foods and drinks. It is also largely ignores gender: women in rich countries are more penalised for being overweight or obese, by society and by themselves, and the "thin ideal" is promoted as empowering and healthy, when evidence for the latter at least is largely lacking.

Nor does Why Calories Count say much about class; although there is a clear summary of the key science and historical mistakes about under-nutrition, there is no discussion of poverty's role. It is the poorest in poorer societies who lack calories: reproducing UN tables comparing national average calories in rich and poor countries does little to aid understanding, and compounds the problem that estimates of calorie availability are not good indicators of what poor people have to eat.

Nevertheless, as a pointer to the science and politics of calories, the book does exactly what it says on the cover.