Despite concerns about the consequences of obesity, correcting calorie imbalances presents challenges few countries are prepared to meet.
When our then-editor at the University of California Press, Stan Holwitz, suggested that we write a book about calories, we said yes right away. Consumption of too few or too many calories is an important -- arguably the most important -- cause of public health nutrition problems in the world today. Problems with calories affect billions of people in rich as well as poor countries. Consuming too few calories leads to malnutrition (undernutrition), which makes people more susceptible to infectious disease. The result is stunted growth, misery, and premature death in children and adults. More than a billion people, most of them in poor countries, go hungry for lack of food.
At the same time, just as many people in the world are consuming more calories than they need and becoming overweight and obese. The numbers of obese people are rising rapidly, even in the poorest countries. Obesity is now so common that the populations of some poor countries contain nearly equal numbers of people who are undernourished and overnourished. Obesity raises risks for any number of chronic diseases, most notably type 2 diabetes.
Public confusion about calories is widespread, has been studied extensively, and is entirely understandable.
The health consequences of too many or too few calories threaten to overwhelm the resources of individuals, families, and health care systems. Countries can ill afford the costs of health care for obesity-related chronic or infectious diseases or to have large segments of their populations unable to work or function adequately. Some analysts even suggest that the health burdens of obesity alone may shorten overall life expectancy within the next few years .
Despite widespread concerns about the health and economic consequences of obesity on the one hand and undernutrition on the other, correcting calorie imbalances presents social and economic challenges that few countries are prepared to meet. Calories, therefore, affect societies in ways that are political as well as personal.
Calories, of course, derive from food. But calories are a convenient way to say a great deal about food, nutrition, and health. For this reason, and because calories are so poorly understood, we thought it would be useful to research and write about calories in all of their dimensions -- personal, scientific, and political. And because we are both consummate "foodies" who derive enormous pleasure from eating, we liked the idea of using calories as a way to think about these aspects of food.
Let's be clear from the beginning: This is not a diet book with a breakthrough scheme for losing weight and keeping it off. Instead, we try to provide an appreciation for what you are up against if you want to control your body weight in today's "toxic," obesity-promoting -- or as we like to call it, "eat more" -- food marketing environment . We intend this book to give you the information you need to interpret food labels, diet claims, and your own reactions to this food environment. Knowledge, we argue, is not enough to counter the biological urge to eat or the subtleties of food marketing. But it is a powerful first step in developing weight-management strategies that work for your particular body, lifestyle, and food preferences.