Flies will consume and lay eggs in feces. These same flies will then come into your house and then spread disease as they pause on your counter and food. Need I say more about keeping feces cleaned up to prevent this cycle?
Preventing Stool Eating
While most dog owners think this doesn't apply to them or their dog, the shocking truth is that most dogs will engage in this unsavory practice at some point in their life. Dogs evolved as carnivore/scavengers and feces were considered fair game in lean times. To prevent this occasional indiscretion from becoming a life-long habit, clean up feces as soon as possible, especially in young dogs where the problem is most prevalent. At the first sign of this bad habit consider adding an oral product like Dis-Taste to your dog's food to decrease the palatability of the stools.