Investigating the Efficacy of a Mobile App Intervention to Change Youth and Their Families' Health Behaviours

Inclusion Criteria: * Child must be between 10 and 17 years old * Child and at least one of their parents must be able to read at the grade 5 level or above * Parent participant must be the caregiver with whom the child primarily lives * Families must have a computer or mobile device and internet access at home * Child participants must be either overweight or obese, as defined by the age and gender specific WHO cut-offs for children and adolescents aged 5 to 19 Exclusion Criteria: * Diagnosis of any musculoskeletal, cardiovascular, pulmonary, or orthopedic problems or disabilities precluding the participant from being physically active * Any other physical condition that precludes the participant from being physically active * Diagnosis of anorexia nervosa or bulimia nervosa * Diagnosis of Type I diabetes * Dietary restrictions or special diets that limit a participant's ability to eat a variety of foods * Simultaneous participation in another physical activity, nutrition, or weight management study/program * Use of medication, nutritional supplements, or herbal preparations to help lose weight * Pregnancy * A history of psychiatric problems or substance abuse which would interfere with adherence to the study protocol