Study participants and data collection
The data collection was done via conducting structured interviews with KIs pre-and post-intervention. Despite in-person interviews at baseline, follow-up interviews were conducted by phone due to the COVID-19 outbreak. A trained community nutritionist of the project advisory committee conducted all interviews. Based on the CRM protocol, key informants were identified using purposeful and snowball sampling techniques among school personnel, parents, principals and/or nutritionists of public health care and municipal community centers. To provide confident answers and insights, key respondents had at least one year of experience working in each local community and were involved in children’s health and wellbeing. Forty-six interviews were conducted at baseline (22 interventions; 24 controls). In this regard, all baseline participants were approached for follow-up interviews. Each interview lasted an average of 40 min and written informed consent was obtained before each interview (Additional file 