Coach-led vs self-directed habit-based interventions for weight loss in adults with overweight and obesity: a randomised controlled trial

INTERVENTION: Sum Sanos, is a 12‐month, one‐on‐one coach‐led, habit‐based weight loss program. Health coaches meet face‐to‐face with participants (or video call if face‐to‐face is not feasible) on a monthly basis for a 1 hour conversation, and follow‐up with them via a 10‐minute phone call on a weekly basis. The frequency of these follow‐ups is aimed to establish accountability, support and maintain engagement in the program. The methodologies that form the foundation of Sum Sanos are based on evidence of key weight‐loss facilitators; these topics are covered as a module during the monthly sessions (i.e., habit‐change, self‐compassion, mindful eating, setback strategies, etc.). Participants are asked to track their daily habits using a ticksheet. This will be collected by the research assistants to assess adherence. Additionally, the number of monthly coach sessions and weekly phone calls attended will be recorded by the coach. Although there is no specific measure of fidelity, part of the coach's role is to help the participant maintain accuracy and consistency of the intervention. CONDITION: Diet and Nutrition ‐ Obesity obesity;overweight;well‐being; ; obesity ; overweight ; well‐being Public Health ‐ Health promotion/education Public Health ‐ Health service research PRIMARY OUTCOME: Weight change (kg) as assessed by digital scale.[12‐months from intervention commencement] SECONDARY OUTCOME: Blood pressure as assessed by digital bench‐top sphygmomanometer[3, 6, 12 and 24 months] Fruit and vegetable consumption as assessed by self‐reported typical daily intake: "On average, how many serves of fruit and vegetables do you eat a day?". A 'serve' of fruit and vegetable is described. [3, 6, 12 and 24 months] Habit‐strength as assessed by Creature of Habit Scale (COHS) and Self‐Reported Behavioural Automaticity Index (SRBAI)[3, 6, 12 and 24 months] Health‐related quality of life as assessed by Short Form 12 (SF‐12) Health Survey [3, 6, 12 and 24 months] Number of coach follow‐ups as assessed by a study‐specific questionnaire, which is completed by the coach of the participant.[12‐months from intervention commencement] Physical activity levels as assessed by self‐reported 7‐day recall ‐ a questionnaire designed specifically for this study. [3, 6, 12 and 24 months] Self‐regulation of eating as assessed by Self‐Regulation of Eating Behaviour Questionnaire (SREBQ)[3, 6, 12 and 24 months] Temperament as assessed by the Effortful Control Scale (EC). [3, 6, 12 and 24 months] Waist circumference (cm) as assessed by soft tape measure[3, 6, 12 and 24 months] Weight change (kg) as assessed by digital scale.[3, 6, and 24 months] INCLUSION CRITERIA: Aged between 18 and 65 years, have a BMI greater than or equal to 27.0kg/m2, own a smartphone, able to consent for themselves and able to attend all required appointments during the intervention period. Participants will be recruited regardless of obesity‐related comorbidities (e.g., cardiovascular disease and diabetes).