The liver is one of the largest organs in the body. It has many important metabolic functions. It converts the nutrients in our diets into substances that the body can use, stores these substances, and supplies cells with them when needed.n fat metabolism the liver cells break down fats and produce energy. They also produce about 800 to 1,000 ml of bile per day. This yellow, brownish or olive green liquid is collected in small ducts and then passed on to the main bile duct, which carries the bile to a part of the small intestine called the duodenum.