The four food groups in a cheese sandwich are Carbohydrates (found in the bread), Lipases (found in the cheese), Protein (found in the ham) and fibre (found in the tomatoes) .
The first step in eating the cheese sandwich is having it being broken up in the mouth. The teeth break up the food into smaller pieces, making it easier to digest and the amylase in the saliva break down the starch into glucose.
The food then moves down the oesophagus contracting its muscles to move food down to the stomach.
When the cheese sandwich reaches the stomach, it's broken down further by stomach acid. These acids help kill any harmful micro-organisms that may have been in the food. Bile from the gall bladder is also used to digest fats as well as amylase, protease, and lipase enzymes further break down the food into molecules which can be absorbed in to the small intestine
At the small intestine, food is digested into simple molecules to be transferred into the blood stream. Food that could not be digested are then moved to the large intestine where water is removed and the waste is turned to faeces.
Finally, the body excretes the feaces through the anus.