Fidelity and factors influencing implementation of Healthy Me, Healthy: process evaluation of a social marketing campaign for diet and physical activity behaviors of children in childcare

The effectiveness of interventions targeting children's eating and physical activity behaviors through childcare settings is inconsistent. To enhance public health impact, it is imperative to evaluate fidelity of implementing complex interventions in real-world settings. This study evaluated fidelity and contextual factors influencing implementation of Healthy Me, Healthy We (HMHW). HMHW was an 8-month social marketing campaign delivered through childcare to support children's healthy eating and physical activity. HMHW required two levels of implementation support (research team and childcare providers) and two levels of campaign delivery (childcare providers and parents). Process evaluation was conducted among childcare centers in the intervention group (n=48) of the cluster-randomized control trial. Measures included attendance logs, self-report surveys, observation checklists, field notes, and semi-structured interviews. A 35-item fidelity index was created to assess fidelity of implementation support and campaign delivery. The fidelity with which HMHW was implemented by childcare providers and parents was low (mean 17.4 out of 35) and decreased between childcare providers and parents. Childcare providers had high acceptability of the program and individual components (80 - 93%). Only half of parents felt intervention components were acceptable. Frequently cited barriers to implementation by childcare providers included time constraints, parent engagement, staff turnover, and restrictive policies. The lack of observable effect of HMHW on children's dietary or physical activity behaviors may be due to inadequate implementation at multiple levels. Different or additional strategies are necessary to support implementation of multilevel interventions, particularly when individuals are expected to deliver intervention components and support others in doing so.