1. Pre-operative Assessment The following assessments will be performed pre-operatively prior to the scheduled surgical procedure and the results recorded on the appropriate subject report form Verification of pre-operative eligibility criteria Subject demographics (gender, age, race, ethnicity, smoking history) Height, weight, and body mass index (BMI) Comorbidity assessment (prevalence and duration of type 2 diabetes mellitus, sleep apnea, hypertension, dyslipidemia/hyperlipidemia, and other clinically relevant comorbidities as determined by the treating physician), including medications Fasting labs (glucose, hemoglobin, HbA1C, hematocrit, ferritin, albumin, total protein, calcium, parathyroid hormone, vitamin A, Vitamin B1, Vitamin B12, Vitamin D2/3, Vitamin 3, Vitamin K, folic acid, insulin, lipid panel, triglycerides, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), C-peptides, iron, copper, and zinc) Surgical history Health- related Quality of life, as measured by the SF-36 assessment Gastrointestinal symptom rating scale, as measured by the GSRS form GERD HR-QL Pre-operative Dietary Restrictions