This study is designed to translate an evidence-based family-based weight loss treatment for childhood obesity (FBT) into primary care settings using co-located interventionists to serve as a model for care delivered within a patient-centered medical home. FBT will be compared to usual care (UC), and the families will be followed for a 2 year period to assess between group differences in the targeted child and parent outcomes, weight changes in non-targeted siblings who are overweight/obese, parent and child changes in delay of gratification, and how these changes relate to weight loss, and the assessment of how provider attitudes predict their intention to use FBT in the future. The results of this study will inform future dissemination and implementation of FBT into primary care settings.

Family-based treatment (FBT) is a behavioral weight control intervention that targets children who have overweight/obesity and their parents, and has the capacity to improve the weight status of non-targeted family members such as siblings. FBT has significant positive effects on body weight in children for up to 10-years of follow-up, and a robust relationship is observed between child and parent outcomes. FBT's concurrent care of two generations of obesity in the family is more efficacious and cost-effective than if family members are treated by their separate health care providers. Despite its recognized efficacy, FBT is mainly available in specialty clinics and many children fail to receive this guideline-based level of treatment, as recommended by the U.S. Preventive Services Task Force. Primary care offers an optimal setting for delivery of FBT by capitalizing on the established relationship between primary care providers and families. Using interventionists co-located within the primary care setting overcomes barriers posed by fragmentation of care, and lack of provider time and training. One of the challenges to integrating childhood obesity treatment into primary care is optimizing limited health care resources. In behavioral weight loss programs, some individuals learn diet, physical activity, and behavior change information quickly, while others learn more slowly. Individuals also differ in their ability to implement treatment recommendations due to individual differences, such as problems with delaying gratification. FBT accommodates these individual differences by using a personalized system of instruction, or a mastery model, in which the content and dose of treatment is calibrated to the needs of the family, ensuring that treatment effort is consistent with need. This multi-site, clinical trial aims to evaluate over a two year period the effectiveness of FBT delivered by a trained interventionist co-located within primary care plus usual care delivered by the primary care provider (FBT) compared to usual care (UC). Participants will be a representative sample of 528 families with a 6-12 year-old child and a parent who have both overweight/obesity. Weight changes in approximately 228 siblings who have overweight/obesity and between 2-18 years of age will also be studied. This study will test between group differences in child (Primary Specific Aim 1A) and parent (Secondary Specific Aim 1) weight change, as well as weight change in siblings who have overweight/obesity (Secondary Aim 2), changes in parent and child delay of gratification, and how changes in delay of gratification are related to parent and child weight changes (Secondary Aim 3), participant level predictors of treatment success (Secondary Aim 4), and how provider attitudes toward evidence-based treatment and perceptions of FBT may relate to their intention to use colocated FBT in their practices in the future (Exploratory Aim 1). Establishing that FBT can be effectively implemented within real world settings is crucial to creating a system by which children and their families who suffer from obesity can be treated in a centralized primary care setting.

Inclusion criteria:

The participating child will be between the ages of 6 and 12 and have a BMI above the 85th percentile for age and sex. The participating child will have at least one parent who has overweight or obesity (BMI>25) and who must agree to attend all parent/child treatment meetings as the participating parent. For families in which one parent has overweight/obesity, this parent will be required to be the participating parent in order for the family to be eligible for the study; if two parents have overweight/obesity, the family will choose one parent to enroll in the study. Similarly, if two children in the family have overweight/obesity, it will be encouraged that the older sibling be the primary participant, as it is more likely the younger sibling will model the older sibling. Though only the child who has overweight/obesity and the participating parent will be required to attend treatment sessions, all family members living in the household, including other adults and siblings, will be encouraged to participate indirectly by supporting changes in the family's lifestyle. Because a secondary aim of the study involves the tracking of treatment effects through the household to non-targeted siblings, heights and weights of at least one sibling with overweight/obesity (BMI>85th percentile for age and sex)in the family will be collected, if applicable. Only siblings ages 2- 18 would qualify. All participants must be able to speak and comprehend English at a first-grade level.

Exclusion Criteria:

The participating parent or child will not have had a concussion in the past three months; will not have any significant developmental delays or intellectual disabilities; will not be receiving treatment for a Diagnostic and Statistical Manual Diploma in Social Medicine (DSM-5) disorder that interferes with treatment delivered as part of the intervention; will not have a physical disability or diagnosis that prevents performance of physical activity at a level equivalent to a brisk walk or that places severe restriction on diet; will not be on a medication regimen that affects weight; will not have a medical condition that alters nutritional status, intestinal absorption, or affects weight; will not have undergone weight loss surgery; and will not be participating in an alternate weight control program. Families in which either the participating child or parent is actively involved in other weight-loss treatment, is using weight-affecting medications, or has an impairing psychiatric or medical condition that would hinder participation in the study will be excluded as identified by the screening assessments. Families that are planning to move or in which the participating parent is pregnant or is planning on becoming pregnant during the 2 year study period will also be excluded.

Parents, targeted children are included in the baseline analysis

Adverse events and Serious Adverse events were collect over the full two year study, 24 month +/- 3 months.

A systematic survey was administered at each measurement time point for the family. Non-systematic adverse events were collected by the coaches if they shared during treatment session with their coaches over the two year study.

Assessor will be blinded to the families group assignment. Coaches will be back up assessor. Coach 1 will be an assessor for families assigned to Coach 2, Coach 2 will collect measures for families assigned to Coach 3, and Coach 3 will collect measures for families assigned to Coach 1. Thus, coaches will not collect height and weight measures for families from their caseload.

Although not possible to guarantee that coaches are blind to condition for families that are not in their caseload due to the families not being blinded, use of a standard protocol (see Appendix C) ensures objective and reliable measurement of the primary outcome. Assessors will be blind to prior heights/weights, further protecting against assessment bias.