I was in one of the first training platoons in the Army which received the "newfangled" MREs instead of C-Rations. Although they were colloquially called "Meals Ready to Excrete" by the "early adopters" of such a technology of cuisine, it felt like they traveled at Mach 2 through the digestive system until the last "quarter mile" of the intestinal tunnel. Then they seemingly sat there for days.
Much of the above activity was due to the famously known "Dehydrated Beef Patty" and "Dehydrated Pork Patty." No matter how much water you added to them, they went down like shredded corrugated cardboard, exhibiting the same gustatory and gastronomical effects.