For awhile. But continued immobility would lead to diminished bowel motility, which in turn would cause all the moisture in the unexpelled fecal matter to be absorbed through the lower intestinal wall. The accumulated fecal matter that had already been expelled and densely compacted by her sheer weight, would also block any further elimination. As the hardened, impacted bowell mass continued to accumulate, she would be chronically constipated. The urge to defecate would probably subside altogether at this point.
It's not unheard of for surgeons to have to remove a hundred pounds or more of impacted feces from the chronically, pathologically constipated.
How could the body continue funtioning with all that old fecal matter? It seems the person would die of internal poisoning... We had to put our horse down last week because he had a bowel obstruction. He was only totally blocked for 3 days before we were forced to put him down. How could a person keep eating or not have terrible abdominal pain ofr so long? GROSS!