The research team is recruiting 900 children between the ages 5-17 with obesity from Tennessee and Louisiana. The team is assigning children and their caregivers by chance to one of five groups. In the first group, 300 children and their caregivers receive 26 hours of IBT. In the second group, 300 children and their caregivers receive 13 hours of IBT. The remaining three groups of 100 children and their caregivers receive 16, 19, or 22 hours of IBT.

Children's healthcare providers, nutritionists, and social workers are providing IBT to each of the groups over six months. At the start of the study and again after one year, the research team is measuring the children's body mass index, or BMI. BMI is a measure of a person's body fat based on their height and weight. The team is also looking at the children's:

• Diet
• Exercise
• Sleep
• Media use
• Quality of life

The Dose study aims to evaluate the optimal number of contact hours (i.e., dose) of intensive behavioral lifestyle interventions for childhood obesity. Current recommendations by the American Academy of Pediatrics (AAP) and the United States Preventive Services Task Force (USPSTF) suggest that intensive behavioral lifestyle interventions should have at least 26 hours of contact time. This is a difficult standard to achieve, as it requires significant resources from healthcare systems and time from families. This study's purpose is to test whether 26 hours is needed to achieve clinically meaningful reductions in child weight among children with obesity.

The investigators will conduct a randomized clinical trial (RCT) where children are randomized to one of five treatment intensities: 26 hours, 22 hours, 19 hours, 16 hours, or 13 hours. The study will use a non-inferiority design: can equal effectiveness be achieved comparing the 26-hour standard to reduced intensities?

900 children with obesity ages 5-17 years old will be randomized, with a focus on rural and minority communities in Tennessee (TN) and Louisiana (LA). The study will engage approximately 15 clinics in TN and 15 in LA.

The intervention will be integrated into local pediatric primary care practices. Participants in all arms will receive the same number of visits with their child's primary care provider (4 visits, 1 hour total), on-demand web-based learning modules that focus on building skills and knowledge in health behaviors (7 hours), and community resource counseling sessions delivered by a social worker or similar healthcare professional (4 sessions, 2 hours total). The difference between arms will be in the frequency and duration of personalized nutrition counseling delivered by a registered dietitian or similar healthcare professional: 16 sessions (60 minutes per session), 12 sessions (60 minutes per session), 9 sessions (60 minutes per session), 8 sessions (45 minutes per session), or 6 sessions (30 minutes per session).

The primary outcome is child body mass index (BMI) expressed as a percentage of the 95th percentile (%BMIp95) of the CDC growth curves, over 12 months, measured approximately 5 times. Our primary hypothesis is that 13-hours will be non-inferior to 26-hours. The analysis also includes multiple, pre-specified sub-group analyses, as there may be important subgroups who require more than 13 hours (e.g., children with a very high starting BMI). Secondary outcomes include changes in child quality of life and health behaviors. The analysis will assess reach, feasibility, and accessibility of this approach for both participants and pediatric healthcare providers, guided by the RE-AIM framework.

Inclusion Criteria:

• BMI≥95th percentile for age and sex based on standardized CDC growth curves.
• parent/caregiver aged ≥ 18 years old
• are comfortable speaking and reading English or Spanish;
• are a patient of a participating clinical practice;
• are able to provide written or verbal consent/assent;
• are able to attend scheduled sessions in the 12-month study;
• are willing to make behavioral and lifestyle changes;
• are able to access the internet to participate in online intervention components;
• complete baseline data collection, including child height and weight; and
• complete at least 90% of baseline survey items no later than 14 days after the baseline visit.

Exclusion Criteria:

• families for whom the primary care provider (PCP) or site principal investigator (PI) thinks the study and/or intervention is clinically/medically inappropriate (e.g. developmental delay, disordered eating, mobility impairments, cognitive or mental difficulties);
• participant child is taking weight management medications at the time of enrollment;
• participant child plans to undergo bariatric surgery or another weight loss operation during the 12-month study; or
• participant caregiver-child dyad has plans to move during the 12-month study and will no longer be a patient of a participating clinic.