BackgroundObesity management presents a persistent challenge. Bariatric surgery, recognized for its transformative impact on weight loss and comorbidities, demands a thorough examination of its long-term implications. ObjectivesOur goal is to investigate different aspects of bariatric surgery, such as complications, comorbidities, infection rates, the long-term sustainability of weight loss, and factors predicting weight loss over an extended period following the procedure. SettingThis study involves 100 patients who underwent primary bariatric surgery. Methodsa sophisticated Longitudinal Observational Study design. With a Retrospective Component and a Follow-Up Component spanning eight years. ResultsThe study included participants with a mean age of 36.4 years (±12.1) and a pre-surgery BMI of 44.5 kg/m² (±7.5). Excess Weight Loss (%EWL) peaked at 75.09 % by the third year, while Total Weight Loss (%TWL) sustained at 33.41 % after two years. Among individuals with type 2 diabetes, medication discontinuation rates reached 26.3 % at 5 years. Zero leaks, a low incidence of major complications and no incidence of mortality have been noted. In an extended 7-year follow-up, 40 % of patients experienced weight regain. Multivariate analyses identified age and preoperative BMI as negatively associated significant predictors impacting %EWL at three years, with standardized beta coefficients of −0.488 (p = 0.001) and −0.450 (p < 0.001), respectively. Conversely, smoking and Type 2 Diabetes Mellitus exhibited positive associations, with standardized beta coefficients of 0.336 (p = 0.004) and 0.286 (p = 0.063), respectively. ConclusionsBariatric surgery is acknowledged as a safe and efficacy procedure for reducing weight and comorbidities, with a relatively low incidence of major complications.