The number of days a person can live without food varies widely, based upon factors that include but are not limited to physiology, overall health and whether or not liquid is consumed. Reliable data on the survival rate of healthy individuals who were hydrated are reportedly scarce. Famous hunger striker Mahatma Gandhi, who was 77 and slight of frame, survived 21 days of complete starvation with only sips of water. In those who do not eat or drink, death typically occurs after 10 to 14 days.
Physiology, Outside Factors and Survival
The number of days a person can survive without food depends on his starting weight, the initial amounts of fat and muscle, water consumption, his basal metabolic rate, or BMR -- the rate at which the body at rest consumes calories -- and the number of calories lost by physical effort. The environmental temperature affects the outcome, as the body burns extra calories in hot or cold environments to maintain a normal temperature. According to an article published on the website Slate in 2004, a person cannot survive losing more than 40 percent of his body mass. When a body does not get food, it begins to use glycogen stored in the liver, which suffices for one to two days. Afterward, the body breaks down fat and then muscle. A healthy person who has approximately 24 lb. of fat can last up to 60 days.
Hunger Strikes and Life-Prolonging Techniques
Bobby Sands, a hunger striker in a 1981 Irish protest, survived 66 days without food. He and his fellow strikers reportedly supplemented their fluid-only diets with spoonfuls of salt. If they had not, their bodies would have become depleted of sodium, causing blood pressure to drop dangerously low. Turkish Marxist hunger strikers, who protested their country's shift from dormitory-style prisons to Western-style cells, consumed salt, unrefined sugar and vitamins to slow their weight loss to a few ounces per day. This helped some of them to live up to 300 days without food.
Starvation and the Mind
According to an article published on website Professor's House, medical doctors, doctors of philosophy, psychiatrists and scientists are reportedly examining the connection between the mind and its ability -- or lack thereof -- to keep human beings alive through sheer will. The article contends that a will to live prolongs a person's life in a starvation situation. For example, political prisoners who are starved often have a strong will to live, whereas terminally ill patients often desire to be at peace and pass on. Some people survive without food for weeks; others have starved to death in days.
Anorexia and End-Stage Disease
Someone with a low BMR, such as a person suffering from anorexia, burns fat and muscle more slowly. Patients with severe anorexia commonly die from organ failure or heart attack when their body weight has fallen to 60 to 80 lb. At this point, their body mass index, or BMI, a measure of percentage of body fat, is typically 12 to 12.5; a normal BMI is 18.5 to 24.9. A person with end-stage cancer often dies after losing 35 to 45 percent of his body weight. An obese person who starves himself might lose more than 45 percent of his mass, but he will last longer than an anorexic patient, because his body can subsist off the excess body fat.
References
- Slate; How Long Can You Go Without Food?; Brendan I. Koerner; June 2004
- HealthHype.com; How Long Can a Human Survive Without Food or Water?; Jan Modric
- Professor's House: How Long Can a Person Live Without Food?
- "Scientific American"; How Long Can a Person Survive Without Food?; November 2004
- American Council on Exercise; BMR Versus RMR; April 2010
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