OBJECTIVE Weight loss induced by the complete resection of insulinoma is controversial in overweight patients. The study sought to explore postoperative weight loss and metabolic changes in overweight insulinoma patients. METHODS A retrospective study was conducted to review the follow-up data of insulinoma patients with a BMI ≥25kg/m2 who underwent complete lesion resection between May 2010 and May 2015. Body mass index (BMI), weight loss (WL) and percentage weight loss (%WL) were main outcomes. RESULTS Fifty-one patients were included with a median follow-up of 28 months. The BMI at 3 months, 1 year, 2 years and 3 years postoperatively were significantly lower than the preoperative BMI values (p < .01). The WL% was 12.9% at 3 months postoperatively without significant changes throughout the 3-year follow-up. WL and the %WL were significantly higher in the high BMI group (BMI≥ 27.5 kg/m2). Multivariate analysis indicated that higher initial BMI was associated with increased weight loss (p = .001). 63.8% of patients with hypertension recovered and improved sleep quality was evident in all patients with obstructive sleep apnea syndrome within 1 year postoperatively. CONCLUSIONS Weight significantly decreased postoperatively in overweight insulinoma patients, which was more evident in patients with higher BMI and metabolic comorbidities were largely improved.