The impact on patient outcomes of a five session, tailored nutrition and dietetic intervention for outpatients receiving psychological treatment for an eating disorder: a proof of principle study

The study intervention will comprise of ten 50 minute sessions of individual face to face “treatment as usual” psychological intervention with a clinical psychologist at Basten & Associates clinical psychology practice + five 50 minutes sessions of individual face to face nutrition and dietetic intervention. Psychological "treatment as usual": Psychological intervention will be delivered weekly. All clinical psychologists at Basten & Associates are trained in the use of cognitive behaviour therapy-enhanced (CBT-E), motivational enhancement, schema therapy, family-based therapy and dialectical behaviour therapy, all of which are known to have effectiveness with eating disorders. Treatment needs for each patient are adapted based on several factors: • The motivational status and readiness for change of the client; • Their diagnosis e.g. binge eating disorder is treated differently from binge-purge subtype anorexia nervosa; and • The patient’s weight e.g. for instance a low BMI requires an early focus on weight restoration above all else. Therefore, TAU within the practice where patients will be recruited is a broad set of options that can be summarised as universal (done with all clients) and optional (likely to be used, depending on the type of presentation). Universal interventions include: • A thorough assessment process • Forming a therapeutic alliance • Developing a formulation • Identifying maintaining factors including adaptive functions for the individual • Psychoeducation about dieting issues • Commencing some form of self-monitoring (e.g. of eating and its antecedents or just emotions) • Weighing and discussing weight trajectory over time • Selecting goals collaboratively with the patient. Optional interventions are more numerous and include the following: • Recommendations for normalising eating (differs for anorexia nervosa, bulimia nervosa and binge eating disorder) • Addressing fear of weight gain through cognitive therapy informed by motivational interviewing • Identifying fears of change (other than fear of weight gain) and addressing each concern thoroughly • Behavioural experiments • Teaching cognitive therapy skills (targeting fear of weight gain, importance placed on weight and shape, core self-worth) • Exploring personal idiosyncratic cognitive errors (such as dichotomous thinking) • Teaching emotional regulation skills other than cognitive therapy • Teaching interpersonal skills (e.g. assertiveness, expressing needs, decision-making, developing closeness, building sensitivity to criticism) • Targeting perfectionism with cognitive therapy • Targeting core self-worth with cognitive therapy and schema-focused therapy • Targeting body-image distress with approaches such as psychoeducation, limit avoidance, limit checking, thought challenging, attentional retraining, behavioural experiments and mirror exposure Nutrition and dietetic intervention: An individual, face to face nutrition and dietetic assessment will be conducted by investigator and dietitian Caitlin McMaster with all participants at two time points: 1) Once participants have consented to be involved in the study, and 2) Once participants have completed 10 sessions of psychological intervention (TAU) and 5 sessions of nutrition and dietetic treatment. Both nutrition and dietetic assessments will have two components: 1) Thorough nutritional assessment conducted by specialist dietitian Caitlin McMaster as per the Position of the American Dietetic Association: nutrition intervention in the treatment of eating disorders recommendations. 2) 24 hour dietary recall conducted using the National Cancer Institute’s online Automated Self Administered 24 Hour Recall (ASA-24) program with guidance from Caitlin McMaster. Participants will receive five 50 minute sessions of individual, face to face nutrition and dietetic intervention in addition to the 10 sessions of psychological TAU as described in the "comparator/control treatment" section. The nutrition and dietetic treatment will take place at the same practice location where the participant is receiving psychological treatment for their eating disorder. The five sessions of nutrition and dietetic intervention will be delivered on a weekly to fortnightly basis. As intake into the study will occur after session 3 of psychological treatment, the nutrition and dietetic sessions will occur between session 4 and session 10 of the participant's psychological treatment. The nutrition and dietetic treatment will comprise of: • Review of patient progress and feedback • Nutrition education (i.e. Macronutrients, micronutrients, core food groups, fluid intake, importance of calcium, fun foods, social eating and diet foods, consequences of starvation/malnutrition and eating disorder behaviours, Importance and benefits of regular eating, importance of targeting feared foods, disordered behaviours involved in food choice and preparation, minimizing vs maximising meal plan, making choices at the supermarket and in social situations, tackling barriers to meal plan compliance) • Education on food and eating skills (i.e. Structure of meal plan, “Thirds rule” for main meals, mechanical eating, increasing regularity of eating, food monitoring, eating with support, meal planning, behavioural experiment framework for feared foods, managing barriers to meal plan adherence, skills to decrease use of disordered behaviours when choosing and preparing food, practical assistance with measuring portions, managing supermarket shopping, targeting common “minimizing” of meal plan, helpful and unhelpful strategies to maintain and build on improvements, treatment planning) • Homework tasks (i.e. construct food hierarchy, practice mechanical and regular eating,eat with others where possible, behavioural experiments targeting feared foods, practice strategies to ensure adequate portion sizes, shop for groceries utilising strategies discussed, practice skills discussed to target meal plan minimizing) Nutrition education, education related to food and eating skills and homework tasks will include the use of informational resources (written resources and worksheets developed by the Centre for Clinical Interventions - https://www.cci.health.wa.gov.au/Resources/For-Clinicians/Eating-Disorders).