How does the intestine break food into small parts my body can use?
When the food you eat reaches the stomach, it gets broken down by a mixture of acid and powerful enzymes. It then moves to the small intestine where 90% of the digestion and absorption happens⁴⁴.
Your small intestine makes digestive juice, which mixes with bile and pancreatic juice to complete the breakdown of proteins, carbohydrates, and fats. Bacteria in your small intestine make some of the enzymes you need to digest carbohydrates. Your small intestine moves water from your bloodstream into your GI tract to help break down food. It also absorbs water with other nutrients⁴⁴.
Digested food stays there for 4 hours until the intestine has absorbed all the nutrients and the waste is passed on the large intestine. Food waste moves through the large intestine where more water and nutrients are absorbed so that a stool is formed. Normally, it takes 36 hours for the stool to get through the large intestine before you pass it out of your body⁴⁴.