The objective of this study was to conduct a comparative analysis about food knowledge and food consumption in preschool and school-age children, their parents and teachers to establish a baseline for a nutrition education intervention model in schools. For that purpose, surveys were administered about healthy and non-healthy food knowledge and food consumption. Results showed an excellent healthy food knowledge and food consumption in children. In parents, despite a good knowledge about healthy food, consumption was unhealthy. The same situation was found in teachers. Distribution of food during the day showed that 98% of parents had breakfast; 96% had lunch, and 77% had an afternoon snack instead of dinner (just 55% had dinner). The number of pre-school age parents who ate dinner was significantly higher than school-age parents. Pre-school age parents did not give money to their children to buy snacks at the school; however, a third of the school-age parents gave money to their children. This demonstrates a major care for healthy food in pre-school age children that is not maintained during the first school grades. This study shows the need to design food and nutrition education programs considering the present food knowledge and food consumption of pre-school and school age children, their parents and teachers.