Unless your digestive system expedited something that did not sit well, chances are the colors of your last meal aren’t coming through in your poop. And your pee certainly doesn’t look like that water, coffee or soda you’ve been drinking. What gives?

MinuteEarth explains (video below) how your red blood cells play a role in the color that comes out of you, once they give up all their oxygen-attracting iron and their empty shells are broken down by your body and the nice, friendly bacteria in your digestive system.

Read: Poop Has Been Used As Medicine — A Lot

There’s a lot more to your poop than its color. Texture and density are also indicative of your health. For example, if your poop floats it means that there is too much fat in it.

And when it comes to your urine, you shouldn’t be chasing after the much-revered colorless pee — your urine may be yellow even if you are completely healthy.

See also:

Grunting Makes Pooping Harder

Here’s Why Coffee Makes You Poop

Is Poop a Form of Birth Control?