The healthy individual requires approximately 100 mL of water per 100 calories ingested to help with metabolism and the elimination of wastes. The two main body means for regulating water levels are the thirst mechanism and antidiuretic hormone (ADH). Both methods are sensitive to osmolality and to changes in extracellular fluid volume. Two hormones, aldosterone and atrial natriuretic peptide (ANP), are helpful in eliminating sodium for the regulation of fluid overload.