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.
Water politics
According to the WHO, each human being requires a bare minimum of 20 litres of fresh water per day for basic hygiene; this equals 7.3 cubic metres (about 255 ft) per person, per year. Based on the availability, access and development of water supplies, the specific usage figures vary widely from country to country, with developed nations having existing systems to treat water for human consumption, and deliver it to every home. At the same time however, some nations across Latin America, parts of Asia, South East Asia, Africa and the Middle East either do not have sufficient water resources or have not developed these or the infrastructure to the levels required. This occurs for many varied reasons. It has resulted in conflict and often results in a reduced level or quantity of fresh water per capita consumption; this situation leads toward disease, and at times, to starvation and death.