Calories are the source of health problems affecting billions of people in today's globalized world and these units of energy are a mystery to many of us. Marion Nestle (Paulette Goddard Professor of nutrition, food studies and public health at New York University and visiting professor of nutritional sciences at Cornell University) and Malden Nesheim (Cornell University Provost Emeritus and Professor Emeritus of nutritional sciences) draw from their recent book, “Why Calories Count” to explain what calories are and how they work, both biologically and politically. While highlighting the ways that federal and corporate policies have together worked to create an "eat more" environment in the United States, “Why Calories Count” reviews the fundamental issues of dieting, weight gain, loss, and obesity, and provides readers with the necessary information to interpret food labels, evaluate diet claims, and understand evidence as presented in popular media.