The objective of the study is to evaluate whether a less intensive intervention, Guided Self-Help Family Based Treatment (gshFBT), is non-inferior to the more intensive Family Based Treatment (FBT) for childhood obesity on child weight loss over 18-months. Cost-effectiveness of both treatments will also be compared.

The primary aim of this project is to determine whether gshFBT is non-inferior to FBT for childhood obesity on child weight loss. Four assessments will be conducted; baseline (month 0), month 6 (post-treatment), and at month 12 and month 18. Assessments will include the following for child and parent: anthropometry, physical activity, nutrition, and cost-effectiveness. Cost-effectiveness will be calculated from a societal perspective and a third party payor perspective. This program of research has the potential to advance the standard of practice for children who are overweight or obese by providing a less intensive but more cost-effective intervention.

1. An overweight child age 7-12, whose BMI is ≥ 85th percentile but does not meet criteria for severe obesity (i.e., BMI ≥120% of the 95th percentile or an absolute BMI ≥ 35 kg/m2 , whichever is lower for age and gender)
2. The parent willing to participate can read English at a minimum of a 5th grade level
3. Parent and Child willing to commit to attending all treatment and assessment sessions and be randomized to either treatment arm
4. Child or parent is free from psychiatric illness than may affect participation;
5. Child does not have any medical conditions that impact weight or may affect participation in physical activity or treatment
6. Child is not taking medications that may impact their weight (unless medication dosage is stable and not for the purpose of impacting weight and appetite)