This study aims to examine the effects of an intervention model, "Change Nutrition by Doing," in which children act as agents of change -- by 'doing' -- in taking responsibility for the contents of the lunch box they bring from home to consume at an early childhood centre. This quasi-randomised case-control trial consisted of 35 Israeli kindergartens whose teachers were participating in an in-service training programme of an intervention model for improving children's healthy nutritional behaviour. The control group consisted of 26 kindergartens whose teachers were participating in other in-service training programmes. The intervention model ran for eight months. The quality of the contents of the children's lunch box in the experimental groups was measured pre- and post-intervention through structured observations that yielded standardised scores. Mann-Whitney U Test for independent samples (at the kindergarten level) was employed to compare the change in lunch-box content across the controls. The results showed that in all the variables the difference between the intervention and the control kindergartens was significant, p< 0.002. It was concluded that the intervention had a significant positive impact on the content of the lunch boxes. This study shows the potential of supporting children to be change agents at home. In the future, there should be a follow-up of the family's perseverance of the acquired habit.