Being overweight or obese is a public health problem. This work evaluated a food and nutrition education (EAN) intervention against overweight schoolchildren in four schools in the West Panama Province. A quasi-experimental before-and-after study that implemented a 34-week EAN intervention through workshops with didactic material to 403 children between 8 and 13 years old. The knowledge and attitude survey was used as an evaluation tool before and after the educational intervention. The prevalence of excess weight (40%) did not report differences after the intervention. No differences were reported in the median level of attitude, although higher levels of knowledge were reported in students of both sexes. EAN in schoolchildren can be effective in acquiring knowledge and maintaining a positive attitude towards food.