Denosumab to Prevent High-Turnover Bone Loss After Bariatric Surgery

Inclusion criteria: * Postmenopausal women who are planning RYGB or SG surgery * Men aged ≥ 50 years who are planning RYGB or SG surgery Exclusion criteria: * Prior bariatric surgery * Weight = 400 lbs (due to limitations of bone imaging equipment) * Renal disease * Hypercalcemia or hypocalcemia * Hypomagnesemia * Serum 25-OH vitamin D (25OHD) \< 20 ng/mL * Hyperparathyroidism * Liver disease (AST or ALT \> 2 x upper normal limit) * HCT \< 32% * History of malignancy (except basal cell carcinoma) in the past 1 year * Significant cardiopulmonary disease * Major psychiatric disease * History of celiac disease or inflammatory bowel disease * Excessive alcohol or substance abuse * Paget's disease, primary hyperparathyroidism, or any other known congenital or acquired bone disease other than osteoporosis * Current hyperthyroidism or use of levothyroxine with TSH \< 0.1 uIU/mL * Current use of loop diuretics * Current use or use in the past 12 months of oral bisphosphonates or DMAB * Current use or use within the past 3 months of SERMs or calcitonin * Current use or use within the past 3 months of estrogen * Use of testosterone therapy if dose has changed within the last 3 months, or if dose change or discontinuation is planned in the upcoming 18 months * Any current or previous use of teriparatide, strontium, or any parenteral bisphosphonate * Use of oral or parenteral glucocorticoids for more than 14 days within the past 6 months * Extensive dental work involving extraction or dental implant within the past 2 months or planned in the upcoming 18 months * DXA BMD T-score of \< -3.0 at PA spine, total hip, or femoral neck * Current use of anti-VEGF drug