Abstract

According to the World Health Organization (2016), 1.9 billion adults over 18 years are overweight (BMI
25 kg/m2), whereas 650 million are obese [1]. Obesity is thus considered as an epidemic worldwide, which is widespread across age, socioeconomic status, and development level of the countries [1]. According to the McKinsey World Institute (2014), obesity is the third social burden on which more money is invested in the world [2]. Bariatric surgery (BS) is considered as an effective treatment for weight loss, which is sustained in the long-term, improving also comorbidities related to obesity such as type 2 diabetes [3]. Currently two procedures are commonly practiced: sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (GB). These surgeries have important differences regarding the procedure, preoperative period, and short- and long-term outcomes. SG is considered a restrictive procedure, consisting in the reduction of the size of the stomach, therefore reducing food intake. In GB, a division is made in the stomach, to create a stomach pouch that connects with the distal jejunum, preventing food from passing through the distal stomach, the duodenum, and the proximal jejunum. GB is characterized both by a restriction in food intake and a reduction in the absorption of nutrients (malabsorptive). A metaanalysis of 21 studies concluded that at the second year postprocedure, GB patients have a significantly greater weight loss compared to SG [4]. In addition, a better control of type 2 diabetes has been observed in GB, displaying a similar improvement in the rest of the comorbidities. GB is the preferred procedure for severe obesity, accounting for 46.6% of all bariatric surgeries [5].