Question (Aim) 1: To what extent does weight loss and weight regain differ across the three bariatric surgical procedures at 1, 3, and 5 years? This aim addresses the primary outcome of interest among most patients seeking bariatric surgery - the differential impact of these procedures on maximum weight loss as well as the extent of longer-term weight regain. We will also explore the heterogeneity in weight loss and regain across several key subgroups that may have differential response to surgical treatment, specifically groups defined by age, race/ethnicity, baseline BMI, smoking status, and pre-operative comorbidities.