How long can a person survive without eating?

Thirst is worse than hunger: Without water, people die within a few days. But how long can we endure without food in an emergency?

Normally one would like to see concrete scientific questions answered with concrete experiments – but not in this case. Unfortunately, one can look back on the fate of many involuntary or ultimately determined people, whose starvation is precisely documented. One of the longest cases dragged on for 73 days: Cork mayor Terence Joseph McSweney died in 1920 on a hunger strike in a London prison protesting the murder of his predecessor. This made McSweney’s fellow prisoners survival records: They had continued the hunger strike started with McSweney until they gave up after 94 days – alive. In October 1929, they were replaced by Bhagat Singh when the Indian socialist stopped a hunger strike on the 116th day in British custody. The length of his hunger period is not without controversy, because the British authorities had apparently made various attempts to force-feed the prisoners or secretly supply them with nutrients, for example through milk in the drinking water.

Officially, this has set a benchmark of at least three months that other famous cases cannot reach: Mahatma Gandhi, for example, fasted on a hunger strike for 21 days; a couple who crashed in an inhospitable area involuntarily for about 42 days. The death of other hunger strikers in various prisons, who died after 28 to 40 days, is officially documented. Long after Irish freedom fighter McSweney, ten political prisoners went on a hunger strike in 1981 after 46 to 73 days.

Further observations suggest that people survive three months without eating – however, these mostly come from hardly controlled circumstances such as concentration camps or starvation disasters and are therefore not very reliable. What is clear, however, is that you always have to drink enough and therefore have to take vitamins and minerals every now and then. Because without water, every person dries out within a few days until the circulation collapses and you die. Exactly how long this takes depends on the general condition. Some of the case studies are well known: If relatives decide that a patient with the most severe brain damage should no longer be kept alive artificially, it often takes about 10 to 14 days after the devices are switched off until they die. It takes a similar length of time if patients in the final stage of an incurable illness voluntarily forego food and drink.

How long you can endure with water but without food then depends on a few other factors. On the one hand, of course, the starting weight before starving, i.e. your own fat and muscle mass reserves. Various indications suggest how much of this weight can melt until inevitable death: Cancer patients in the end stage lose around 35 to 40 percent of their body mass until they finally die. But people are also known to be very overweight, who lose significantly more body mass percentages on a strict diet – obviously, fat reserves serve as a hunger buffer. When anorexics who are severely anorexic are approaching death, their body mass index (BMI) drops to around 12 to 12.5, almost half of the average normal value, which is between a good 18 and just under 25. The cause of death is then about 20 percent of those affected organ failure or heart attack. By the way, the risk of a heart attack has also ensured that physicians today, even those who are completely healthy, urgently advise against the zero diets that were popular decades ago.

An almost as important role as the starting weight before the time of hunger also plays the individual expression of the metabolism, which can be more or less used to a longer phase with low calorie gain. This is how people survive a total lack of food better if their energy metabolism – such as the thyroid function – can flexibly adjust to the lack of food. A pronounced hunger metabolism usually has disadvantages for abundantly cared for people, my nutrition experts: diabetes or anorexia could be more common among those affected. In the special case of a starvation catastrophe, however, such people may have survived more often in human history – which is possibly the reason why certain types of diabetes genes have not long since become extinct.


Eating and drinking are basic human needs. If the body is not supplied with nutrients, it is not efficient and will eventually switch off completely.

How long can you survive without food?
While people can get by without drinking for up to four days, it is considerably longer when they eat. People can survive up to 60 days without food. But what does this depend on and what are the consequences?

  • There are well-known examples of hunger strikes such as Mahatma Gandhi, who went hungry 17 times, for up to 21 days. He and others remained without consequential damage.
  • When we go hungry, the body switches into a kind of hibernation, which means shutting down the less vital systems.
    Heart rate, blood pressure and body temperature are lowered to use less energy.
  • The body first goes to the protein in the muscles and then breaks down stored fat. The body then breaks down the organs to supply the brain with nutrients.
  • The organs can shrink in half. Ultimately, it depends on the situation and in extreme situations people have repeatedly achieved incredible performance.
  • An overweight Scotsman who fasted for 382 days and lost 124 out of 206 kg was rather unusual. However, doctors urgently advise against such radical cures.

But please take enough food with you on your next camping tour or hike. A lack of food can mean that you do not have enough energy to continue your tour. So always think of sufficient food intake!

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