Body Size Estimation in Eating and Weight Disorders

Abstract

Body image disturbance is a core feature of eating disorders and is also mentioned as being relevant for the development and maintenance of obesity. Despite its important role in conceptualizations of eating and weight disorders and their treatment, there is still a remarkable lack of knowledge about the specific characteristics of body image disturbance. The present thesis uses an updated theoretical framework and a multi-method account involving innovative methods to disentangle and evaluate the role of different body representations for body image disturbance. A transdiagnostic perspective is adopted, with a focus on anorexia nervosa. The thesis encompasses four sub-projects. Study A provides a systematic review and meta-analysis of body size estimation accuracy in anorexia nervosa and bulimia nervosa. Unlike previous reviews, it uses an updated theoretical framework of body size estimation that accounts for method-specific differences in the assessed representations. Study B applies the theoretical framework to multi-method data obtained from obese children in weight loss treatment, compares their performance to that of normal-weight children and provides an overall analysis of associations between different measures. Study C uses a technically innovative body size estimation paradigm along with other measures to evaluate different components of body representation in women with anorexia nervosa and healthy controls and associations between different measures. Study D uses optimized figure rating scales as a quick and easy means of evaluating body image disturbance in anorexia nervosa and additionally examines effects of scale range and associations with other measures of body representation. Wrapping up the different studies, the project yielded clear evidence of a cognitive-affective disturbance characterizing body image disturbance, but no hint of a visual perceptual distortion in the sense of disturbed awareness in eating and weight disorders. On a conceptual level, the project supports the perspective of body representation as a conglomerate of different representations that are mutually interacting. In this perspective, it is overly simplistic to speak of disturbed body perception or general cognitive-affective disturbance. Rather, body image disturbance should be understood as a phenomenon arising from disturbances in single representations or their integration. Clinically, the present projects demostrates that although inaccurate body size estimation frequently occurs in eating and weight disorders, it is not due to a general lack of awareness regarding the own size. The present results also emphasize differences between body image disturbance in obesity and anorexia nervosa. While obese individuals mainly suffer from high body dissatisfaction, body image disturbance in anorexia nervosa seems to be characterized by incoherent representations of the body. Further research is needed to clarify to what extent this is due to disturbances in isolated representations or to integration processes.