A intragastric device that contains a compressible free-floating structure and a sleeve attached thereto is provided. The device is considered to be anchorless as the sleeve is not physically attached to any portion of the GI tract. The device is configurable between a compressed pre-deployment configuration and an expanded post-deployment configuration. The free-floating device may be composed of a shape memory material such a nitinol. In some embodiments, the free-floating structure is space occupying and non-porous. The sleeve may be attached to the free-floating structure, such as with sutures and/or glue. In some embodiments, a stent may be inserted at the proximal end of the sleeve. A second free-floating structure may be connected to the free-floating structure such that there is an upper structure and a lower structure. In some embodiments, the gastrointestinal device is used to deliver prebiotic and/or probiotic therapy to a patient.