From the time food enters the mouth, enzymes are at work breaking the food down into smaller and smaller components until it can be absorbed through the intestinal wall and into the blood stream. Raw food naturally contains the enzymes necessary to aid in digestion. When raw food is chewed, enzymes are liberated to aid in digestion.
Amylase reduces complex carbohydrates to simpler sugars like sucrose, lactose, and maltrose.
The lipase enzyme turns fats into free fatty acids and glycerol. Ideally, the human body is capable of producing similar enzymes, with the exception of cellulase, necessary to digest food and allow for the absorption of nutrients. Estimates, however, of as many as twenty million Americans suffering from various digestive disorders, would indicate that optimal conditions are not the case. Most food enzymes are functionally destroyed at the temperature used to cook and process food, leaving food without natural enzyme activity. The body needs a certain amount of enzymes to properly digest food and thus must produce more of its own enzymes in order to make up the difference.