Obesity is a chronic disease characterized phenotypically by an increase in body weight (BMI\>30 kg/m2) and by a series of associated pathologies, such as hypertension, diabetes, hepatic steatosis. The association of these pathologies compromises the patient's survival and quality of life. The multifactorial origin of obesity makes its etiopathology difficult to manage. It is often possible to follow only one therapeutic strategy, especially after the so-called standard treatments, such as dietary intervention and physical activity, have not brought benefit to the patient. In these cases, an appropriate treatment for the patient to enjoy significant weight loss is bariatric surgery. Bariatric surgery refers to all those interventions aimed at reducing weight in those suffering from obesity, and treating the diseases associated with it. Among the different types of bariatric surgery, the techniques most used in common clinical practice are intragastric balloons, gastric by pass (RYGB) and sleeve gastrectomy. The choice of the surgeon, assisted by the multidisciplinary team, is binding in the choice of the type of operation to which the patient will be subjected.