The present invention provides, compositions, devices; and methods for affecting, among other things, weight loss and/or weight control, by sequestering nutrients or other compounds such as toxins from absorption in the digestive tract. The compositions, devices, and methods employ one or more members made of a compressible, absorbent matrix material. In various embodiments, the matrix material is suitable for routine use. The compressible absorbent matrix material has a size, shape and/or geometry configured for efficient packing into a small space, and/or configured to absorb and substantially retain digested material in the stomach. The devices and compositions may further comprise one or more hydrogel(s), soluble or insoluble fibers, waxes and/or gums to provide the desired mechanical properties and/or absorptive or shielding properties.