After being churned up in your stomach, small amounts of liquified food enter your small intestine for digestion.
The pancreas can make up to 3 pints of digestive juices each day used to break down proteins, fats and carbohydrates. The lives produces bile salts which are stored in the gallbladder and released into the small intestine to help the body further digest fats.
Once digested, the nutrients in your food can then pass through the mucosal lining of your small intestine and into your bloodstream for nourishment.
What's left is undigested food matter that enters the large intestine where water is absorbed making the undigested matter harden. It moves to the rectum and is excreted as feces.
If the food you are eating has little nutrients or you can't digest your food for some other reason then there can be a blockage of undigested food in your intestines. This can seep into the bloodstream and because it is undigested your immune system attacks them and you may feel ill.
Some problems faced by people with food intolerances and poorly digested food are migraines, dermatitis, colitis, severe bowel toxicity, gastritis, issues of the gallbladder, insulin resistance and food allergies.