If feces is the bits of food that our body couldn’t digest or use, is it possible to eat a diet that our bodies can use 100% and never have to defecate? And, if so, could such a diet ever be healthy or would it always be deficient in some nutrients?

Question

If feces is the bits of food that our body couldn’t digest or use, is it possible to eat a diet that our bodies can use 100% and never have to defecate? And, if so, could such a diet ever be healthy or would it always be deficient in some nutrients?

In: 90

Answer 1

I don’t know if I’ve seen someone address it specifically, but your question premise is wrong, that’s not what feces is. It does contain some food we couldn’t or didn’t digest, but that’s not most of it.

You get energy from the food by changing chemical bonds, not from using it up and making it disappear.

It sometimes helps people to think of it like a car. You put gas in and then it emits exhaust. No matter how efficiently you drive you aren’t going to make a car that doesn’t exhaust anything (assuming it runs in gas obvi).