The present invention provides systems and methods for treating and controlling obesity and/or type II diabetes. In one aspect of the invention, a bypass device includes gastric and duodenal anchors coupled to each other and positioned on either side of the pylorus and a hollow sleeve designed to extend from the pylorus through at least a proximal portion of a patient's small intestine. The gastric and duodenal anchors are movable between collapsed configurations for advancement through the esophagus and an expanded configuration for inhibiting movement of the anchors through the pyloric sphincter. Thus, the bypass device can be placed and removed endoscopically through the patient's esophagus in a minimally invasive outpatient procedure and it is “self-anchoring” and does not require invasive tissue fixation within the patient's GI tract, thereby reducing collateral tissue damage and minimizing its impact on the digestive process.