Human nutrition is the provision to humans to obtain the materials necessary to support life.
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. Lack of food remains a serious problem, with
about 36 million humans starving to death every year. 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 to almost epidemic proportions, leading to health complications and increased mortality in some developed, and a few developing countries. Obesity is caused by consuming more calories than are expended, with many attributing excessive weight gain to a combination of overeating and insufficient exercise.