ACTyourCHANGE Study Protocol. The Promotion of Healthy Lifestyle for Obese Patients with Acceptance and Commitment Therapy provided with A Modular Approach.

Background: Acceptance and Commitment Therapy (ACT) resulted to be efficacious in promoting the core process of Psychological Flexibility, a key ability related to physical and psychological health outcomes. Despite evidence-based ACT protocols were applied successfully in different contexts, including the promotion of long-standing behavioral change, the impact of the single processes in the psychological flexibility model remains unclear. The aim of the present study is to evaluate the efficacy of a Focused-ACT intervention for the maintenance of a healthy lifestyle, by separating and evaluating the impact of single core processes targeted into a modular intervention on the maintenance of healthy lifestyle. Methods: An individually randomized group treatment trial will be conducted. 150 adult obese patients who are attending a four-week medically-based multidisciplinary rehabilitation of weight loss will be randomly allocated into three groups: Module Engage, Module Openness, and Module Awareness. At the beginning (Time 0) and at the end of the intervention (Time 1), at six months (Time2) and one year (Time 3) follow-up weight and height will be recorder and participants will complete the Psychological General Well Being Inventory(PGWBI), the Outcome Questionnaire-45.2 (OQ-45.2), the Brief Values Inventory (BVI), the Committed Action Questionnaire (CAQ), the Italian-Cognitive Fusion Questionnaire (I-CFQ), the Acceptance and Action Questionnaire (AAQ II) and the Five Facet Mindfulness Questionnaire (FFMQ). Repeated measures 3 (conditions) x 4 (times) will be assessed to examine differences between three groups within four times on both general outcomes measure of weight, BMI, PGWBI and OQ-45.2, and FACT processes targeted during the interventions.Discussion: By providing additional evidence supporting the relevance of modular transdiagnostic interventions in clinical practice and the use of Process-Based Therapy, this study will contribute toclarify which mechanisms are involved in a generalizable lifestyle behavioral change intervention. Trial registrationClinicalTrials.gov Registration number: NCT04474509 Date: July, 4 2020 https://clinicaltrials.gov/ct2/show/NCT04474509