Background: The WHO defines obesity as an excess deposit of fat that can be harmful to health with a great social impact. In the last two decades, bariatric surgery has increased as an alternative to reduce excess weight and body fat, of which we highlight the vertical gastrectomy. Objective: To describe the change in Body Mass Index, dietary behaviors, and physical activity in a group of patients undergoing vertical Gastrectomy surgery in a clinic in Medellin, Colombia between 2016-2018. Materials and Methods: Retrospective descriptive study, in which medical records were reviewed in 49 patients, 13 men and 36 women, who underwent vertical gastrectomy in a private clinic in Medellin. Results: Patients started with an average BMI of 34.2 kg/m2 and one year post-surgery they descended to an average BMI of 24.4 kg/m2 (p=0.00); also, an improvement in eating habits such as eating between meals, and less consumption of sweets and soft drinks was found. Conclusions: Vertical Gastrectomy surgery proves to be an appropriate technique for decreasing BMI, at least in the first year post-operative.