A fat is made up of two parts, one a fatty acid, the other glycerol. Fat cannot be absorbed by the body until it is split into these two parts. A fat splitting enzyme is called a lipase. There is none in the mouth ; one in the stomach works only on fat in the state of emulsion; the most powerful is found in the pancreatic juice. Since fat cannot be digested in the mouth nor to any great extent in the stomach, it is bad to have food coated with it, for the protein and carbohydrates will have to wait till the fat is digested away, before they can be digested ; that is, till the intestine is reached. This is one reason why pastries and fried foods are hard to digest.