BACKGROUND Refeeding syndrome (RFS) and starvation-associated injuries are significant complications in malnourished patients. Severe weight loss after obesity surgery is frequently associated with malnutrition, consequently increasing the likelihood of RFS and starvation-related injuries as postoperative complications. RFS and starvation-induced injury in a single patient has rarely been reported. In this paper, we present, for the first time, a case of hepatic injury attributed to both refeeding syndrome and starvation-induced hepatic injury in a malnourished woman following bariatric surgery. CASE REPORT A 27-year-old female patient was admitted to the hospital for severe malnutrition after sleeve gastrectomy. Her body mass index (BMI) dropped from 37.2 kg/m² to 12.4 kg/m² 1 year after surgery. After nutritional supplementation, her liver enzymes levels increased significantly, with severe hypophosphatemia suggesting the development of RFS. During the calorie restriction treatment for RFS, the patient unexpectedly exhibited the recurrent increase of liver enzyme levels and severe reduction in body weight, albumin, and hemoglobin, which is considered to be caused by starvation-induced injury during the treatment of RFS. Following precise nutritional re-supplementation, her liver enzyme levels were dramatically decreased, with significant elevated hemoglobin and albumin levels at discharge and during the follow-up visit. CONCLUSIONS Chronic malnutrition and extreme weight loss can occur following bariatric surgery. Our report highlights the potential for RFS and starvation-related liver injuries as postoperative complications for high-risk patients after bariatric surgery. Liver injury can occur in both RFS and starvation-induced hepatitis. Nutrition initiation and supplementation should be carefully balanced in high-risk patients during nutritional treatments.