When you eat food, it goes through a series of organs in your body known as the "digestive system." All of these different parts work together in order to get as many nutrients out of your food as possible, before getting rid of the waste (otherwise known as poop and pee!).
The organ where the majority of the food is broken down and absorbed is called the "intestines" (divided into two smaller parts called the "small intestines" and the "large intestines"), which is a long tube food passes through on its journey out of your body. The small intestines are responsible for absorbing the vitamins and minerals from your food, and using them to keep your body strong and healthy, while the large intestines absorbs excess water and stores waste until you can get rid of it.
Depending on a person's height and age, the small intestines can be anywhere from eighteen to twenty-three feet long, and the large intestines are around five feet long! That's a lot of intestines!
If our intestines are over twenty feet long, why aren't we over twenty feet tall? How can we fit all of that inside us?! Even though they're long, the intestines are also narrow, with the small being one to two inches around, and the large being three or four. This allows them to to be folded and coiled up on top of each other, and fit nice and neat into small spaces (namely, your abdomen!).