英文の和訳をお願いします。
Americans are having a passionate love affair with something they cannot see, hear, feel, touch or taste. That something is calories, billions upon billions of which are consumed every day, often unwittingly, at and between meals.
Certainly calories are talked about constantly, and information about them appears with increasing frequency on food labels, menus, recipes and Web sites. But few people understand what they are and how they work - especially how they have worked to create a population in which 64 percent of adults and a third of children are overweight or obese, or how they thwart the efforts of so many people to shed those unwanted pounds and keep them off once and for all.
Enter two experts: Marion Nestle, a professor of nutrition, food studies and public health at New York University; and Malden Nesheim, professor emeritus of nutritional sciences at Cornell University. Together they have written a new book, "Why Calories Count: From Science to Politics," to be published April 1, which explains what calories are, where they come from, how different sources affect the body, and why it is so easy to consume more of them than most people need to achieve and maintain a healthy weight.
