Studying the mechanisms of weight regain (WR) may provide much needed insight into sustained obesity management. The aim of this five-year, prospective, multicenter study is to evaluate the association among eating patterns (specifically maladaptive behaviors), certain psychological variables and weight trajectory in the short- and long-term after bariatric surgery (BS). The study will include 2 groups: 1.- Candidates to primary BS undergoing laparoscopic gastric bypass (LGBP) or laparoscopic sleeve gastrectomy (LSG) from September 2020 to September 2021. This group will be evaluated prior to surgery, at 4 months, 1 year, 3 years and 5 years after BS, and 2.- a control group of subjects with obesity not candidates to BS matched with the intervention group for age, sex and BMI prior to BS. They will be evaluated once. The primary variable will be: body weight: total weight lost (%), excess weight lost (%), total weight regained (%), excess of weight regain (%). Information regarding the psychological and behavioral variables will be collected using questionnaires that have been validated in our setting and will be completed by the patients themselves online.