many fasters report that they can "feel better" after an enema/colonic, because they get rid of toxins instead of having their kidneys, lungs and skin removing them.
And you cannot bring up hibernating animals. It's a different process. Fasting/starving animals don't lie in bed but run around in search of food -- and true, they poop on their own, without enemas. Experienced fasters also poop on their own lol after having run couple of miles. Again, the metabolic processes go on during a fast as usual, and wastes are dumped into the GI tract. That's the gurgling people experience. They should take a look what comes out the other end lol instead of keeping it in for the duration of the fast.