Chemical Digestion When the body can not break down food by the physical means it has, the body must therefore use chemical digestion to help finish the job. Chewing food with teeth is an example of physical digestion, but that is just the beginning of the process. Chemical digestion is also occurring at this starting point where digestive juices begin to counteract with the food to begin to break it down into a digestible matter.

As the digestive fluids begin to act upon the food, the small molecules are being transformed into other elements to fuel the body. Some food such as proteins, carbohydrates lipids or fats are too large to be simply absorbed by the body and chemical digestion directly affects how these molecules are digested. The main reason...

In other words they do not dissolve in water.
As this type of food is eaten, it is broken down by the teeth by chewing as much as possible, the saliva in the mouth also simultaneously begins the chemical digestion process to assist in the mechanical or physical aspects of the digestion process. As the food is processed it is next swallowed and enters the esophagus. The stomach is the next stop and this is where many chemical reactions begin to happen to break down the food into energy.

An acidic chime from the stomach blends with the food as it enters the small intestine. As this happens two hormones are being secreted into the blood: cholecystokinin…