Aims/Background Gastric cancer is a common and life-threatening cancer, which predisposes patients to certain psychological problems. Implementation of both personalized nutrition and acceptance and commitment therapy (ACT) have shown unique advantages in the treatment of cancer patients. This study aims to evaluate the effects of this comprehensive therapy on psychological resilience, quality of life and side effects of chemotherapy in patients with advanced gastric cancer (AGC), yielding findings that can inform the development of holistic and effective treatment methods. Methods The clinical data of 240 AGC patients who underwent chemotherapy in the Fourth Hospital of Hebei Medical University from February 2021 to February 2023 were retrospectively analyzed. After excluding 15 patients who did not meet the inclusion criteria, 225 patients were included in the study. According to the management methods, the patients were divided into three groups: group A receiving routine management (n = 76), group B receiving routine management plus personalized nutrition (n = 75), and group C receiving routine management, personalized nutrition and ACT (n = 74). The psychological resilience, quality of life and side effects of chemotherapy were evaluated in the three groups. Results There was no difference in the Connor-Davidson resilience scale (CD-RISC) scores and quality of life questionnaire-core 30 (QLQ-C30) scores among the three groups at admission (p > 0.05). After chemotherapy, compared with the group C, the CD-RISC scores of group A and group B were significantly lower (p < 0.001), and the scores of physical function, cancer-related symptoms and overall health in group A and group B were significantly lower (p < 0.001). The incidence of side effects of chemotherapy in group C was 25.68%, which was significantly lower than that in group A and group B (p < 0.05); there was no statistical difference in this regard between group A and group B (p > 0.05), and the same parameter was significantly different between group A and group C (p < 0.05). Conclusion Personalized nutrition management plus ACT has a significant favorable effect on improving psychological resilience, alleviating the side effects of chemotherapy, and enhancing the quality of life in patients with AGC undergoing chemotherapy.