Apparatus and methods are provided for partitioning a gastro-intestinal lumen by intraluminally reducing a local cross-sectional area thereof. The apparatus comprises a plurality of anchors adapted for intraluminal penetration into a wall of the gastro-intestinal lumen to prevent migration or dislodgement of the apparatus, and a partition, which may include a drawstring or a toroidal balloon, coupled to the plurality of anchors to provide a local reduction in the cross-sectional area of the gastro-intestinal lumen.