When the fat moves down your digestive tract into your small intestine, an intestinal hormone called cholecystokinin alerts your gallbladder to release bile. Bile is an emulsifier, a substance that enables fat to mix with water so that lipases can start breaking the fat into glycerol and fatty acids. These smaller fragments may be stored in special cells (fat cells) in adipose tissue, or they may be absorbed into cells in the intestinal wall, where one of the following happens:

They’re combined with oxygen (or burned) to produce heat/energy, water, and the waste product carbon dioxide.