Although motivation has long been regarded as essential for behavior, very little research has been done on its role in behavior change. This paper focuses on this issue by examining motivations for eating and dieting in obese and anorexic patients. Measuring the commitment to eating and the commitment to dieting, the study finds that motivations which influence behavior are often not immediately obvious. The dual issues of the motivations underlying a disorder and the motivations connected with seeking treatment, as examined in people with weight control problems, are relevant to most problems treated with psychotherapy. The paper concludes that without greater study of patient motivations, effective treatment of patients will remain a difficult problem. (Author/FC)