The first edition of this book had two main goals: to strengthen connections between the eating disorders and obesity fields, and to provide a comprehensive and authoritative account of knowledge in the two areas. To what extent were these goals realized? It is our view that we accomplished the second goal but were only partly successful in achieving the first—the separation between the fields remains too large. It is still the case that there is too little exchange between the two areas and it is still true that there are few people who are knowledgeable about both fields.
Yet many issues are common to the two areas. The first is the basic physiology and psychology of hunger and satiety, and the processes that underlie weight regulation. Much is known about these matters and knowledge is increasing. For example, one notable advance has been the discovery of leptin and the elucidation of its contribution to the regulation of energy balance (see Chapter 6), yet its clinical importance remains unclear. What is the contribution of leptin to the development and maintenance of obesity, and what is its relevance to eating disorders (see Chapter 48)? These fundamental questions remain to be answered.
Another area of common interest is binge eating. Here there has been more progress stimulated to a large extent by the provisional new eating disorder diagnosis “binge eating disorder” (see Chapter 31). It is now established that a subgroup of people with obesity have a frank eating disorder (although many people with binge eating disorder are not overweight) and these people appear to be especially prone to gain further weight. So in binge eating disorder we have a disorder that lies right on the interface between obesity and eating disorders.
Body image is a third common area. The overevaluation of body shape and weight is a central feature of most eating disorders (see Chapter 29) but body image concerns are also present among some people with obesity albeit generally to a lesser extent (see Chapter 72). In the eating disorder field, body image was the subject of much research in the 1980s, but this declined during the 1990s in part because of difficulties of conceptualization and measurement. There are now signs that research on body image is on the increase and we hope this will benefit both fields.
Cognitive-behavioral therapy is another potential link between the two fields. Cognitive-behavioral theory is well established as being relevant to the understanding of