The purpose of the study is to develop and test the feasibility of a structured, innovative approach to treat obesity in 16 children (age 3 to 10 years) with autism spectrum disorder (ASD). This 16-week program integrates behavioral psychology and nutrition science to meet the challenges of obesity in children with autism spectrum disorder (ASD). The PI will apply an evidence-based behavioral intervention to increase food variety,15 use applied behavior analytic strategies to teach physical activities in a developmentally-appropriate manner, employ biometrics to assess progress, utilize dietetic interventions to improve nutritional balance, and train caregivers to use behavior management strategies.