The aim of this study is to perform a randomized controlled trial for patients undergoing bariatric surgery, comparing the need for opiates with and without administration of a transversus abdominis plane (TAP) block using the long acting local anesthetic, liposomal bupivacaine (Exparel®). From this study, the investigators will assess whether use of long acting local anesthetic can reduce the need for opiates in the bariatric population.