Ingestion is the process by which food is broken down through mechanical breakdown with your teeth and chemically broken down with saliva produced in the salivary glands.
Digestion is the process of the trachea contracting and relaxing to push the food down into your stomach where it starts to achieve the ultimate goal, Breaking down the macro molecules into smaller more manageable molecules.
Mechanical breakdown continues in the stomach where the muscular walls of the stomach contract and relax to mix the food in with the gastric acid and enzymes which provides further chemical breakdown as well.
Chemical Breakdown is when the liver gall bladder and pancreas secrete more enzymes to further breakdown the food while it is being transferred through your intestine. This is the final step in breaking down food macro molecules into smaller molecules.
By now, most of the macro molecules have been broken down to small enough sizes that they can be and absorbed into the plasma and provide enragy for the organs and cells that need it
The left over food which the body doesn't need is now poo and is stored in the rectum until a 'suitable' time. Once the time is right it is passed through the anus and has now left the body.