How parents feed their children who show high levels of food approach behaviour is a key intervention target, but we lack longitudinal and experimental evidence to unravel cause and effect relationships in this context and have yet to identify the levers for behaviour change in children with these characteristics. The APPETItE study will provide this evidence by implementing the following protocol. The initial stage of this research examines the dynamic relationship between children's food approach (FA) behaviours and parent feeding practices over multiple time points (at age 3 months, 1.5, 3, and 5 years) using autoregressive cross-lagged structural equation models (SEM). In the second stage, an online survey will be distributed to identify a sample of 3-5-year-old children with high FA behaviour, using Latent Profile Analysis (LPA). Primary caregivers with children classified by LPA as high in FA will then document their child’s eating behaviours and feeding practices using Ecological Momentary Assessment. The feeding practices determined by the SEM and EMA phases will contribute to the empirical investigation of specific feeding practices in an experimental setting. In each feeding practice condition, 3-5-year-olds with high FA and their primary caregivers will be invited to the child-eating laboratory to receive one of three feeding practice interventions. The results of all work packages will be collated with the views of parents and other stakeholders regarding the content and delivery of a targeted intervention to improve outcomes for children with high food approach.