All living organisms require food as the source of energy; however, the way in which each organism obtains it may vary from one another. This energy is required to carry out various growth and developmental activities in our body. A body may use the raw materials to build up new components by the process of anabolism. It may also decompose the material into its simpler form by the process of catabolism. Anabolism when coupled with catabolism is called metabolism.
Digestion involves breaking of complex food into its simpler form by making use of digestive enzymes present in mouth to the intestines. This process then releases energy that is absorbed by our body. Such process is an example of chemical reactions involved in the process of food breaking (catabolism).