Infant feeding practices in the first 2 years of life are linked to long-term weight trajectories. Despite the importance of obesity prevention interventions, there are no randomised controlled trials (RCTs) evaluating early childhood education and care (ECEC) and primary caregiver-targeted interventions on child weight and feeding outcomes.

To assess the efficacy of an 18-month digital health intervention (Tiny Bites) delivered to ECEC services and primary caregivers of children aged 4 to ≤12 months on child age-adjusted and sex-adjusted body mass index-for-age z-score (zBMI) relative to usual care control in the Hunter New England (HNE) region of New South Wales, Australia.

This type 1 hybrid cluster RCT will include up to 60 ECEC services and 540 children/caregiver dyads. The intervention supports ECEC services and caregivers to deliver recommended responsive feeding practices to infants. ECEC services will receive access to an online assessment platform, training and resources, and implementation support. Primary caregivers will receive text messages, monthly e-newsletters, online links and direct communication from ECEC services. We will assess the impact on child zBMI at 18-month follow-up. Secondary outcomes include duration of consuming any breastmilk, child diet and caregiver responsive feeding practices. We will also assess ECEC policy and practice implementation related to targeted feeding practices, programme cost effectiveness, adverse effects and engagement with the programme (ECECs and caregivers). For the primary outcome, between-group differences will be assessed for paired data using two-level hierarchical linear regression models.

Ethics approval has been provided by HNE Human Research Ethics Committee (HREC) (2023/ETH01158), Deakin University (2024-202) and University of Newcastle HREC (R-2024-0039). Trial results will be submitted for publication in peer-reviewed journals, presented at scientific conferences locally and internationally and to relevant practice stakeholders.

ACTRN12624000576527.