Human
In general, humans can survive for two to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days. About 36 million humans die every year from causes directly or indirectly related to starvation. Childhood malnutrition is also common and contributes to the global burden of disease. However global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed, and a few developing countries. Worldwide over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an "obesity epidemic." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet.
Suicide methods
Death from dehydration can take from several days to a few weeks. This means that unlike many other suicide methods, it cannot be accomplished impulsively. Those who die by terminal dehydration typically lapse into unconsciousness before death, and may also experience delirium and deranged serum sodium. Discontinuation of hydration does not produce true thirst, although a sensation of dryness of the mouth often is reported as "thirst." The evidence this is not true thirst is extensive and shows the ill feeling is not relieved by giving fluids intravenously, but is relieved by wetting the tongue and lips and proper care of the mouth. Patients with edema tend to take longer to die of dehydration because of the excess fluid in their bodies.