The objective of this study is to evaluate the effects of 'high' versus 'low' volume intraoperative fluid administration (Ringer Lactate, RL) on intra- and postoperative parameters, in obese patients undergoing laparoscopic bariatric surgery (i.e., gastric bypass), in order to establish evidence-based data for perioperative fluid management in this patient population. Based on their experience as well as several reports in the literature, the investigators hypothesized that a restrictive approach to intraoperative hydration will reduce the incidence of postoperative complications and the recovery time of gastrointestinal (GI) function, and shorten hospital stay.