The present study is intended to retrospectively compare the short-and long-term outcomes of 3 different treatment methods in patients undergoing bariatric surgery and the variances in weight and nutritional parameters during the preoperative and postoperative periods. In this study, 534 patients who underwent laparoscopic sleeve gastrectomy (LSG), laparoscopic Roux-En-Y gastric bypass (LRYGB), and laparoscopic one anastomosis gastric bypass (LOAGB) between 2014 and 2021 were included. The sociodemographic and biodemographic characteristics of these patients, their weight losses and nutritional changes in the preoperative and postoperative periods, operative times, hospital stays, complications, and morbidity and mortality rates were retrospectively compared. There was a statistically significant difference between the surgical methods in the percentages of excess weight loss and total weight loss in the 1st and 3rd months. There were significant differences in the homeostasis model assessment of insulin resistance, folic acid, vitamin D, iron, ferritin, and parathyroid hormone levels (P < .05). All 3 techniques were found to be successful in facilitating weight loss at the end of the first year. LRYGB and LOAGB were found to be superior to LSG in terms of remission from diabetes during the first 6 months, whereas LSG was superior to the other methods in terms of nutritional deficiencies. Despite being more advantageous in terms of operative time, LSG and LOAGB were disadvantageous compared with the LRYGB technique because of the higher rates of leakage and mortality in the LSG technique and the higher rate of bile reflux in the LOAGB technique.