Description
As the writing of this textbook was concluding in 2010, The Strategic Plan for NIH Obesity Research was released for public comment. The research plan starts with a simple description of obesity resulting from a mismatch in energy balance, whereby calories taken in from food and beverages exceed those expended in activity and metabolic functions to result in excessive adipose tissue (body fat) storage. From this straightforward beginning, the plan goes on to describe the many ways in which the growing prevalence of obesity is a highly complex phenomenon, requiring multifaceted research in a wide variety of disciplines. Obesity research is conducted at a number of levels, focusing on molecules, cells, tissues, organs, systems, and behaviors throughout the lifecycle at the individual level as well as the interplay of factors and dynamics that prevail in families and communities which are influenced by social, economic, and political realities prevailing in the United States in the 21st century and in developed and developing countries around the globe.
Reflecting that complexity, this book is presented to the reader in 27 chapters, organized into five parts. The first four chapters, constituting Part I, help the reader understand the scope and complexity of the problem of obesity. Part II focuses on obesity etiology—a topic so complex it requires six chapters, ranging from a discussion of genetic and other biological contributions to physiological and environmental factors that are thought to be causal. Part III examines the health consequences of obesity for both children and adults. Part IV discusses the challenge of assessing obesity in humans and offers insights into community factors that influence the risk of obesity. Finally, Part V dedicates 13 chapters to a discussion of a wide variety of prevention and obesity treatment interventions currently in use. The authors of each chapter were asked to identify questions that future research might answer.
What we have also strived to capture is the sheer excitement of discovery that drove generations of researchers to make their contributions to our current understanding of obesity. That understanding has grown, piece by piece. But progress is not always incremental. Below we have chosen to describe one example of a revolution in our understanding of obesity. This illustrates not only the excitement of discovery, but also the serendipity that sometimes permits several lines of scientific inquiry to converge into a momentous leap forward. This example informs the way some researchers now think about the interface between genetics and environment—that genetics loads the gun, but environment pulls the trigger.