Cognitive behaviour therapy and motivational enhancement therapy for obese individuals and their support partners.

INTERVENTION: Patients and Support Partners: Obese patients will attend 90‐minute group sessions conducted by a clinical psychologist. The one‐year period of intervention will be comprised of 8 weekly, 16 fortnightly, and 2 monthly sessions. The intervention will entail a combination of cognitive behaviour therapy (CBT) and motivational enhancement therapy (MET) that has been manualised. In the CBT component, patients will be provided with information regarding the dietary and physical activity requirements for weight loss and maintenance, and will be taught a range of behavioural and cognitive strategies to assist with weight control (e.g., self monitoring, stimulus control, goal setting, challenging negative self‐talk, pleasant activity scheduling, problem‐solving, relaxation training, and relapse prevention strategies). The MET component seeks to enhance patients’ intrinsic motivation to control their weight through targeting decisional balance (so that the advantages/pros of weight control come to outweigh the disadvantages/cons) and self efficacy (so that patients are confident that they can effectively control their weight over time). MET components include education regarding the nature of behavioural change (e.g., the stages of precontemplation, contemplation, preparation, action, and maintenance), examining each patient’s pros and cons of weight control (e.g., exploring valued goals and how the patient’s current weight undermines the attainment of these goals), developing alternative means of fulfilling the needs met through overeating or being overweight (e.g., learning stress management strategies if overeating is a means of coping with stress), and building confidence that change is possible (e.g., identifying each patient’s strengths and available supports). The program for the Support Partners of obese patients will be based on programs instructing support partners in motivational strategies for patients with substance dependence and eating disorders. Support Partners will attend 90‐minute group sessions conducted by a clinical psychologist. The one‐year period of intervention will be comprised of 10 sessions. These groups will be run separately to those for the patients. Similar to the CBT+MET intervention for patients, Support Partners will be provided with information regarding the nature of behavioural change, assisted to examine the patient’s pros and cons of weight control, encouraged to generate alternative methods the patient can use for fulfilling the needs met through overeating or being overweight and developing a plan to introduce these methods to the patient, assisted to understand strategies for increasing the patient’s confidence that change is possible, and encouraged to adopt a communication style that is consistent with MET (e.g., being empathic and avoiding arguing or attempting to control the patient). CONDITION: obesity PRIMARY OUTCOME: The primary outcome is the amount of weight loss at post‐treatment and the one‐year follow‐up. Weight will be measured at each visit using an electronic scale with a 200 kg capacity. INCLUSION CRITERIA: The inclusion criteria include: 18‐70 years of age; a body mass index (BMI) between 30‐60; and one support partner who will be available to attend sessions. SECONDARY OUTCOME: A six minute supervised walk test will be performed (after checking with the patient regarding any heart conditions) to assess exercise capacity. Blood pressure will be measured using a standard sphygmomanometer with large cuff. Measurements of abdominal adiposity will include waist circumference, hip circumference, and waist‐to‐hip ratio. Serum metabolic parameters will be assessed in the fasting state including glucose metabolism (blood glucose) and lipid profile (HDL‐cholesterol, LDL‐cholesterol, total cholesterol, and triglycerides). A fasting serum sample will be taken for the measurement of insulin (HbA1c if known diabetes). Assessment of renal function (creatinine, eGFR, and urinary microalbumin), liver function tests, and hsCRP will also be undertaken. The Binge Eating Scale is a 16‐item self‐report questionnaire designed to assess impulsive eating tendencies. The Body Esteem Scale is a 23‐item self‐report questionnaire that assesses general satisfaction with one's appearance, weight satisfaction, and a sense of others' evaluations about one's appearance. The Depression Anxiety and Stress Scales are comprised of 21 items that assess depression, anxiety, and stress over the past week. The standard format will be altered to assess mood disturbance in the previous 4‐week period. The Impact of Weight on Quality of Life Questionnaire‐Lite is a 31‐item self‐report questionnaire which assesses the perceived effect of being overweight on five domains of quality of life: Work, Public Distress, Sexual Life, Physical Function, and Self Esteem. The International Physical Activity Questionnaire‐long version will be administered to assess five domains of physical activity over the preceding 7 days. The National Diet and Nutrition Survey is a four‐day diary developed by the Medical Research Council Collaborative Centre for Human Nutrition Research which will be administered to index the amount and type of food and drink consumed. The Rosenberg Self Esteem Scale is a 10‐item self‐report questionnaire that assesses one's overall evaluation of oneself as a person. To assess social support for weight management, two versions of the Support for Healthy Eating Habits scale will be administered ‐ one for friends and one for family members. Similarly, two versions of the Support for Exercise Habits scale will be administered ‐ one for friends and one for family members. The Quality of Relationships Inventory is a 25‐item self‐report questionnaire that assesses the level of social support, depth, and conflict that an individual perceives to exist in a specified relationship. In this study, participants will be asked to complete the questionnaire in reference to their support partner.