Why do flies eat feces? What kind of nutrition could they possibly get?

Spare nutrients and vitamins are a good start, but did you know that flies are responsible for actually "sanitizing" things! We normally don't associate flies with sanitation, but what flies are looking for on the piles of excretion (which has a TON of bacteria in it--especially bacteria that lives in the colons of the organisms that did the excreting) or garbage are mouth-watering bacterial colonies, which provide a meal all in their own! So, though we usually look at flies for being associated with filth and grossness--it's their job to take that disease-causing bacteria and slurp them up. It's a dirty job, but someone's gotta do it!

Note: Though this may make flies seem a lot cleaner, keep in mind that even the fly has its own harboring bacteria. They are responsible for a lot of disease-spreading in their own right. So, though they eat SOME micro-organisms, they can just as likely bring diseases along. Hope this helps!

poop contains vitamins produced by their intestinal bacteria. The animal is unable to absorb the vitamins through the intestinal wall, but can get at them by eating the poop. Another reason that animals such as dogs and flies eat poop is that poop contains a certain amount of protein.. does that help? but i dont sugest humans eat poo.. it wont help!

all of the spare nutrients that has passed out of the animals body.
the food that goes into the animal is full of nutrients, sometimes not all of those nutrients are needed in the body and leave in the form of poopoo =]
and the flies take that in.