The purpose of the study is to test a novel, acceptance-based behavioral treatment for bulimia nervosa (BN) in adults. This treatment is a type of individual psychotherapy called Nutritional Counseling And Acceptance-Based Therapy (N-CAAT) that enhances existing cognitive behavioral therapy (CBT) for BN by incorporating acceptance-based behavioral strategies and nutritional counseling to help patients eliminate BN symptoms.

Bulimia nervosa (BN) is an eating disorder characterized by a pattern of binge eating and compensatory behaviors as well as an overemphasis on body weight and shape in self-evaluation. BN has a lifetime prevalence rate of 1-3% and is associated with numerous psychiatric and medical complications. Cognitive behavioral therapy (CBT) is regarded as the gold-standard treatment for BN and the treatment approach with the most empirical support to date. However, although CBT has accumulated impressive empirical support for its effectiveness, CBT produces abstinence from binge eating and purging in only 30-50% of treatment completers. Furthermore, relapse is common and many individuals do not maintain treatment gains. Innovative treatments that can improve rates of remission among patients with BN and related disorders are sorely needed for bulimia nervosa and related eating disorders, particularly for individuals for whom existing treatments fail.

Existing CBT may be enhanced by incorporating acceptance-based behavioral strategies and nutritional counseling to help patients eliminate BN symptoms. Acceptance-based behavioral treatments (ABBTs) emphasize "changing what you can and accepting what you can't", which refers to a focus on learning how to accept and tolerate distressing internal experiences (e.g., thoughts, emotions, urges, physical sensations) that might not be directly under the patients' control while choosing to engage in adaptive behavioral choices that are within their control. Patients may benefit from the provision of more adaptive behavioral strategies to maintain weight in a healthy range, which is not a primary goal of existing behavioral treatments. Nutritional counseling (NC), which is designed to promote healthy, non-rigid dietary restraint and exercise habits, can lead to improvements in weight control that may also improve disordered eating behaviors. As described above, a primary maintenance factor for BN is the strict and rigid dieting behavior that triggers urges to binge. Several studies have indicated that the provision of healthy restraint strategies to patients with BN can reduce binge eating and purging behaviors, suggesting that this approach can be an effective treatment alone or in combination with other behavioral techniques.

Study Objectives-

• Test the feasibility, acceptability, and preliminary efficacy of Nutritional Counseling And Acceptance-based Therapy (N-CAAT) for bulimia nervosa (BN) in a small pilot RCT trial
• Assess the mechanisms of action to enhance treatment development
• Evaluate the feasibility of recruitment, randomization, retention, assessment procedures, and implementation of the novel treatment to enhance the probability of success in subsequent larger RCTs

Inclusion Criteria:

• Meets Diagnostic Statistical Manual(DSM)-5 criteria for Bulimia Nervosa
• Age 18 or above

Exclusion Criteria:

• Body Mass Index (BMI) below 85% of ideal body weight or other medical complications that prevent ability to engage in outpatient treatment
• Acute suicide risk
• Co-morbid diagnosis of a psychotic disorder, bipolar disorder, or substance dependence
• Diagnosis of mental retardation or a pervasive development disorder
• Current pregnancy