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.
Global public good
Although not the only example, no better example can be found than the issue of potable water. Water has always been an important and life-sustaining drink to humans and is essential to the survival of all known organisms. Over large parts of the world, humans have inadequate access to potable water and use sources contaminated with disease vectors, pathogens or unacceptable levels of toxins or suspended solids. Drinking or using such water in food preparation leads to widespread waterborne diseases, causing acute and chronic illnesses or death and misery in many countries. While the global water cycle is the subject of advanced scientific study and observation, it is still an incompletely understood process. If availability of water for human consumption is left solely to market forces, those who are most in need of water for subsistence-level survival are also those least likely to be able to purchase it at a market price. Since the water cycle and the natural flows of fresh water resources do not obey the limits of political boundaries, neither can these water resources be managed solely by local- or national-level public authorities. Privatization of such resources can be used as a method of avoiding contentious public policy-making processes, but is likely to produce inequities. The history of the development of water supply and sanitation in Ecuador and resulting water conflicts there are an example. Thoughtful design of transnational or international water management authorities over such global common-pool resources will play a large part in possible solutions to peak water problems.