We drink depending on how mcuh water is available for consumption. If there is a lot of water available we will drink often and urinate often. If there is little water available, the body will conserve wather by increasing the amount of solutes in the urine. There are two different types of thirst, osmotic and hypovolemic. Osmotic thirst occurs when there is an increased level of solute concentrations in the body.
Hypovolemic thirst occurs after an overall loss of body fluid.
In this case the body craves not only water, but also solutes. There are two major types of eating disorders, which are anorexia and bulimia. With increased research and awareness this epidemic can be diminished. People with anorexia eat much less than they need, become extremely thin, and in some cases die. Some people with anorexia show signs of depression, and many have elevated levels of cortisol.