The Canadian pediatric obesity epidemic has led to great interest in evaluating weight management care for obese children and families. Investigation is warranted since obesity is linked to risk factors for chronic diseases including type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). Over the past 25 years, many interventions have studied the role of healthy lifestyle behaviours to help obese children achieve and maintain a healthy weight. A contemporary view of pediatric weight management interventions includes parents as a fundamental recipient of treatment. These interventions recognize the influence parents have on the lifestyle behaviours of their children. While such parent-based interventions have helped establish the role of education and behavioural theory in facilitating lifestyle changes, we believe an equally important intervention element is a focus on the role of cognitions in helping to interpret behaviour change and change maintenance. Our study incorporates cognitive behaviour theory (CBT) into an intervention for parents of obese children and compares it to a more traditional modality based on psycho-education (PEP).

Hypothesis: Obese 8 - 12 year old children (n=45) whose parents complete a 16-session, group-based, CBT intervention will achieve greater reductions in adiposity as well as improvements in physiological risk factors for T2D, lifestyle behaviours, and psychosocial outcomes at post-intervention as well as 6- and 12-months follow-up versus children (n=45) whose parents complete a 16-session, group-based, psycho-education intervention .

Primary Objective: To compare the impact of two weight management interventions (CBT versus PEP) for parents of obese children on child BMI z-score.

Secondary Objective: To measure a comprehensive set of physiological, behavioural and psychosocial outcomes in obese children and parents pre- and post-intervention.

We expect obese children whose parents complete the CBT intervention will experience greater reductions in BMI z-score vs. children whose parents complete the PEP intervention. We anticipate that improvements in parenting style, family stress, and lifestyle behaviours will be important to improve adiposity, lifestyle behaviours, and risk factors for T2DM and CVD in obese children.

Inclusion Criteria: Boys and girls (n = 90) between 8 - 12 years of age with a sex- and age-specific BMI ≥95th percentile are eligible for this study. Children are referred to the Pediatric Centre for Weight and Health (PCWH) at the Stollery Children's Hospital (SCH) (Edmonton, AB, Canada) only if their BMI percentile meets or exceeds this threshold. At least one parent/guardian per family is required to participate in one of the two group-based interventions as agents of change for their family.

Exclusion Criteria: Obese children referred to the PCWH <8 years old will be referred to an outpatient dietitian for nutrition counselling; obese boys and girls >12 years old will be eligible for other weight management interventions at the PCWH. Children who do not have a parent/guardian interested in participating or possess an age- and sex-specific BMI <95th percentile will be ineligible. Children diagnosed with an endocrine disorder (i.e., Polycystic Ovarian Syndrome, Prader-Willi Syndrome, hypothyroidism) will be referred to the Endocrine Clinic at the SCH. Parents or children who are identified at screening as having severe mental health conditions or psychosocial circumstances that could limit their ability to participate in the interventions will be referred to appropriate agencies and services. Impaired ability to participate in either intervention may include substantial difficulties in attendance or implementing changes at home. Referral services may include psychological/psychiatric services, welfare services, and private nutrition or exercise counselling. Dr. Rachel Keaschuk (PCWH Psychologist and Co-I) will perform psychological interviews (75 - 90 minutes) with all families to determine family appropriateness and will lead family discussions regarding referral services (if indicated).