Purpose: The goal of this study was to assess changes in eating self-efficacy after participating in a brief psychoeducational group intervention, grounded in the cognitive-behavioral model, delivered by dieticians in community-based health facilities. Design/methodology/approach: The study was conducted using a quasi-experimental, pre-post design. A total of 110 program participants took part in the study. They were asked to complete the Eating Self-Efficacy Scale before the start of the intervention, at the end of the intervention, and three months after the intervention ended. Data were analyzed using the Linear Mixed Model. Findings: Participants' personal sense of control over their eating behaviors significantly increased after they completed the program and continued to increase up to the three-month follow-up. The effect of the intervention remained significant after controlling for differences in age and whether participants had access to other forms of individual support or completed the follow-up during the COVID-19 general lockdown. Practical implications: By promoting participants' sense of eating self-efficacy, this intervention could lead to positive dietary changes, which in turn could promote better health and healthy aging. Social implicationsL This community intervention is readily accessible and represents a cost-effective approach to promote healthy eating, reducing the risk of chronic disease and the need for medical care, thereby cutting costs for the healthcare system. Originality/value: (1) This study addresses a gap in the scientific literature as there was limited published research to date that investigated this intervention. (2) The three-month follow-up made it possible to evaluate whether changes in eating self-efficacy were maintained over time. (3) Potential confounding variables, including age, having access to other forms of individual support and the COVID-19 general lockdown, were taken into account.