Background: Preschool-age children with developmental disabilities (DD) have higher prevalence of obesity than children without DD. This study aimed to explore the relationship between parent perception of their children’s anthropometric phenotype and child body mass index (BMI) z score change over one school year among preschoolers with DD.

Methods: The analysis consisted of a subsample (N = 64) of children with DD from a larger randomized controlled trial to test an obesity prevention program in the childcare center setting. Parents ranks their child’s anthropometric phenotype on a visual silhouette chart on a scale from 1 (underweight) to 7 (obese) and that rank score is compared to their BMI z score change over one school year.

Results: The majority (75%) of parents with an obese child underestimated their child’s anthropometric phenotype while 7% parents with a non-obese child overestimated. Parent overestimation of child anthropometric phenotype status is associated with increased BMI z score change over 1 school year among preschool-age children with disabilities.