This study is the second of three sub-studies aimed at evaluating the outcomes of the Living Green and Healthy for Teens (LiGHT) program, delivered through the Aim2Be app (v2.2). Aim2Be is an app for 10 to 17 year olds and their families that is intended to help them shift from an healthy lifestyle toward better health habits in four areas: nutrition, physical activity, recreational screen time, and sleep. This second evaluation has the following aims to: 1) describe reach; 2) assess change in knowledge of Canadian health recommendations; and 3) assess change in lifestyle behaviours and weight outcomes and whether these changes are moderated by involvement in the app. This study uses a two-group parallel/crossover randomized controlled trial design following N=200 families for six months.

Living Green and Healthy for Teens (LiGHT v2) is an engaging online, individualized, gamified lifestyle management program for youth, delivered through the Aim2Be app. LiGHT v2 is focused on initiating long-term behaviour change in youth and their families in order to help them shift from an unhealthy lifestyle toward better health habits in four areas: nutrition, physical activity, recreational screen time, and sleep. The program aims to support healthy lifestyles of 10- to 17-year-old children and adolescents, as well as to mitigate increased risk for metabolic and non-metabolic complications associated with obesity in the short and long term.

The app includes content that involve the family, and focus on behavioural therapy as well as dietary and physical activity patterns. Aim2Be is intended to be engaging and fun, provide virtual and tangible rewards, interact with participants multiple times per day, and provide a mobile social support network.

Pre-teens (10-13) and teens (14-17) will each have their own unique versions of Aim2Be. Content will be tailored specifically to the developmental stage and needs of each age group. The content will be delivered in such a way that it facilitates education, peer-to-peer conversation, and self-regulation in an engaging platform.

Because parents have been shown to be of primary importance in supporting healthy lifestyles of children, LiGHT v2 will educated and engage parents as well as youth. Parents will receive separate, but complementary content, intended to guide them as they shop for and prepare food and make behavioural changes within their families. The content for parents will be delivered using the same social aspects of Aim2Be as the pre-teens and teens, but the channels will be gated, so teens and parents each have their own space. Aim2Be's social features will help parents strategize and empathize with other families who wish to adopt healthy lifestyles.

The program will be evaluated using three separate study groups. This protocol describes the second of the three.

Families (one parent and one child) will be recruited through advertising on social media and through active referral from six Canadian Pediatric Weight Management Registry (CANPWR) sites (Children's Hospital of Eastern Ontario, SickKids, McMaster Children's Hospital, Stollery Children's Hospital, Alberta Children's Hospital, and British Columbia Children's Hospital). Approximately 350 families will be recruited and a total of 200 families will be enrolled into the study and randomized into two groups. This study uses a two-group parallel/crossover randomized controlled trial design. All families will be given access to Aim2Be v2.2 to use from their mobile device or home computer. Participants will be prospectively followed for six months.

Once participants are deemed eligible to participate in the study and complete their baseline assessments, they are allocated to one of two conditions: 1) Live Coach; or 3) waitlist control group given standard of care. Participants in the Live Coach group will be given access to Aim2Be for six months with a live coach who has expertise in supporting lifestyle modification and will help youth and parents set goals and achieve these goals using principles from motivational interviewing. Participants in the control group will be wait listed for enrollment in the app for three months and will be given access to the Virtual Coach version of the app after they complete the three month evaluation. The Virtual Coach group version provides automated guidance from a virtual coach instead of a live person, but that is programmed using the same motivational interviewing principles.

Evaluation at baseline, three months, and six months will be used to compare whether those assigned to the different coach conditions have better health outcomes than those assigned to the waitlist control group. Parents will complete questionnaires at baseline, three months, and six months, which assess sociodemographics, behaviours, and mediators of behaviour change. Youth will complete questionnaires at baseline, three months, and six months, which assess health behaviours, mediators of behaviour change, and knowledge of Canadian recommendations for healthy behaviours. Questionnaire data will be collected and managed using REDCap.

Families will be provided with a Fitbit, scale, and measuring tape when they enroll in the study. At each assessment point (baseline, three months, and six months), parents will provide youth's height and weight, and youth will complete three 24-hour dietary recalls and wear the Fitbit for the duration of the study.

Honoraria will be paid at each time point to compensate participation.

Participants will be randomly allocated to each of the two groups and have equal likelihood of assignment to each condition. Participants will not be blinded as the design of the intervention does not facilitate this. Participants will be informed of their allocation after completing all baseline measures. Evaluators and researchers will be blinded to allocation during data analysis.

The aims of this study are to: 1) determine reach/ who participates in this study (short term outcome); 2) determine whether participation in the program increases adolescents' knowledge of Canadian health recommendations related to dietary habits, physical activity, and sedentary behaviour (medium term outcome); and 3) assess the impact of Aim2Be on changes in dietary habits, physical activity, and sedentary behaviours as well as Body Mass Index (BMI) and whether the impact is moderated by involvement in the app (long term outcome).

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