Very light tan colored stool is an indication that the biliary system, the liver, the gallbladder and the bile ducts are not functioning properly, according to the Digestion Relief Center. The problem is typically related to an obstruction that prevents bile from being able to breakdown the fats in the small intestine; however, it can also be related to the stomach. If the stomach does not produce sufficient quantities of stomach acid, it will be unable to trigger the release of bile.
A very light tan colored stool indicates that there is a huge amount of fatty tissues and acids still present that have not yet been digested. Insufficient quantities of bile will also cause problems in the digestion of proteins and carbohydrates. In short, the body will not receive the nutrients that it requires to stay healthy. The inability to digest fat in particular will lead to hormonal imbalances, dry skin and even poor immune function.
To correct and treat this situation, determine what the underlying cause is. Gallstones and biliary sludge can be corrected by making dietary changes, such as taking supplements that support the liver's function; however, if the underlying cause is much more severe, surgery may be required.