Depending on the level of hydration, humans can survive without food for up to 60 days, according to the Public Library of Science. Death typically occurs in 10 to 14 days in patients in a persistent vegetative state who no longer receive sustenance, says Scientific American.
The amount of time a human may survive without food also depends on body weight, genetics and metabolism. Up to 20 percent of patients suffering from anorexia die from organ failure or heart attack when body mass index falls to about half of normal, according to Scientific American. Terminal cancer patients may lose 35 to 45 percent of their total body weight before death.