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.
Salt poisoning
Although humans cannot survive on seawater alone—and, indeed, will sicken quickly if they try—some people have claimed that up to two cups a day, mixed with fresh water in a 2:3 ratio, produces no ill effect. During the 18th century, British physician Richard Russell (1687–1759) advocated the practice as part of medical therapy in his country. In the 20th century, René Quinton (1866–1925), in France, would also endorse the practice. Currently, the practice is widely used in Nicaragua and other countries, supposedly taking advantage of the latest medical discoveries.) In his 1948 book, "Kon-Tiki", Thor Heyerdahl reported drinking seawater mixed with fresh in a 2:3 ratio during the 1947 expedition. The French physician Alain Bombard (1924–2005) survived an ocean crossing (1952–53) in a small Zodiac rubber boat using mainly raw fish meat, which contains about 40 percent water (like most living tissues), as well as small amounts of seawater and other provisions harvested from the ocean. His findings were challenged, but an alternative explanation was not given. A few years later, an American sailor and adventurer, William Willis (1893–1968), claimed to have drunk two cups of seawater and one cup of fresh per day for 70 days without ill effect when he lost part of his water supply.