Effects of combining glucagon-like peptide-1 receptor agonist (GLP-1 RA) treatment with comprehensive personalised behavioural therapy on overweight and obese patients.

Participants in the treatment group will receive weekly subcutaneous injections of 2.5mg Tirzepatide for 4 weeks, with the dose increasing to 5mg from week 5 until the end of the intervention period at 6 months. Tirzepatide will be sent to patients on a monthly basis to self-administer, along with return labels to allow study investigators to monitor treatment adherence (drug vial return). As part of the group's comprehensive behavioural intervention, participants will have access to asynchronous, patient-initiated health coaching 5 days a week, 18 hours a day for the duration of the intervention. Health coaching (diet and exercise) will be delivered by a team of dietitians and mental health nurses through a mobile phone application in the form of videos, text messages, infographics and spreadsheets, and will be personalised for each treatment group participant, based on the assessment of the prescribing doctor and the participant's goal setting sessions with their health coaching team. Each treatment group participant will receive a minimum of 1 asynchronous goal-setting and accountability session (45 minutes) and weekly asynchronous check-ins (15 minutes) for the first 12 weeks of treatment. Participant adherence to the behavioural intervention will be monitored through app analytics of weight-logging frequency, food diary input (text and image), and total app engagement. From months 6 to 12, participants in the treatment group will continue to have access to educational resources and their goals via the program app but will no longer be able to communicate with their multidisciplinary team.