This thesis focuses on the development of negative body image and disordered eating in adolescence. More specifically, on the role of sociocultural influences in individual vulnerability to experiencing negative body image and using disordered eating behaviours.

Eating disorders can be viewed on a continuum, with disordered eating not reaching clinical diagnostic criteria but having potentially negative effects including increasing the risk of an eating disorder or obesity. This study investigated disordered eating in relation to emotional processing from an Acceptance and Commitment (ACT) perspective. Body image dissatisfaction is recognised as a risk factor in eating disorders and was therefore included in this study to investigate whether the ACT concept of inflexibility was associated with ‘less acceptance’ of body image and an increased eating disorder risk as well as general mood disturbance (i.e. depression and anxiety). A non-clinical sample of 96, 12-15 year old females at secondary schools in London was used. Eating disorder risk, inflexibility as well as depression and anxiety were measured. When comparing high, low and moderate eating disorder risk groups it was found that the low and moderate eating disorder risk groups had lower levels of inflexibility and the low eating disorder risk group had a higher body image acceptance than the moderate and the high risk groups as predicted. Inflexibility was also associated with higher rates of anxiety and depression and a negative association was found between depression and anxiety in relation to acceptance of body image. Thus providing supporting evidence for the transdiagnostic significance of ‘inflexibility’. Clinical implications of these findings in relation to prevention and treatment are discussed.