The liver is involved in fat metabolism and synthesises lipoproteins, cholesterol and phospholipids essential for many body functions. Lipids also provide a valuable alternative energy source to glucose and so the metabolic fate of fats and lipids will depend on the levels of intake in the diet and energy expenditure.

If fat is in excess, the liver prepares for storage. Lipogenesis is the metabolic process in which fats, composed of fatty acids and glycerol, are converted for storage in subcutaneous tissue and other storage depots.

If energy and glucose levels are low, stored fat is converted back into glycerol and fatty acids by a process called lipolysis. This occurs in adipose cells, but the fatty acids and glycerol are transported to the liver for use as an alternative energy supply.