How long is it possible to survive by just drinking water and not taking any food? What is the human body’s endurance limit?

At the beginning it is necessary to point out that only an approximate time can be given, because it all depends on various factors such as: health of the starving person, body weight, genetic conditions or physical effort during the starvation.

Do we burn calories doing nothing?

Let’s start with our body. Do we still burn calories while doing nothing? Yes. Even if we lie down on a bed and close our eyes, our body is still using resources. The body has to maintain the right temperature, the muscles responsible for breathing are also working, and the most important muscle in our body, the heart, which is constantly pumping blood. All this comes at a cost in precious calories. How many exactly? It depends on our body weight, and the recommended formula to calculate our own energy expenditure is to multiply our weight by 0.02. An example reader weighing 70 kilograms burns 1.4 calories for every minute of reading this article (assuming he does nothing else at the same time). This means that for 60 minutes the body burns 84 calories and over 2000 calories in a day.

But what happens when we stop supplying calories? The body then begins to use its reserves. At the beginning goes fat tissue. The body of an average woman has 25-31% body fat and a man 18-24%. So let’s assume that our 70-kilogram individual has 20% body fat, or 14 kilograms of fat. It is estimated that 0.45 kilogram of fat is about 3500 calories. With the energy expenditure of such a person, this means losing 1/4 kilogram of fat per day. So that comes out to 53 days. However this is pure mathematics, in practice man still makes some movements. In addition, man does not live by fat alone, thus the body will start to take additional nutrients also from our muscles, which will soon be depleted. Our body takes protein from the muscles, which it uses, among others, to support the brain function.

Effects of starvation

In the initial stage of starvation, there is a significant weight loss, apathy and weakness. This period can last for about 30 days. After this time, the starving person will begin to feel much worse effects. Due to weakness of the body various infections may appear, which our body is not able to fight. Then weakness appears, with which the starving person is not even able to drink on his own. The lack of vitamins causes rashes, swelling and cracking of the increasingly dry skin. Due to muscle atrophy, any movement causes pain. The starving person is also increasingly lethargic. Beyond 40 days, the body will begin to shut down more organs. The last organ is the heart and it is its arrest that is generally considered the cause of death.

Interestingly, even the minimal amount of food taken in, extends life by up to several months. Prisoners of concentration camps and Russian camps, despite receiving starvation rations, were able to survive for a long time and at hard labor. This has to do with the yet unexplored “economic mode” of our body, in which it consumes fewer calories. It is speculated that this has to do with our body’s hormonal balance, specifically the thyroid gland.

No research has been done on starvation, but there are various historical sources about the course of such starvation.

One of the better documented cases is the 1981 Irish hunger strike, where IRA members went on hunger strike in protest. Most of the protesters were relatively young: the youngest was 23 and the oldest 30. The first death occurred after 46 days. The longest survivor was 25-year-old, Kieran Doherty. He survived for 73 days. These events are shown in a film entitled “Hunger.”

Much older in age was Mahatma Gandhi, who at the age of 74, conducted one of his hunger strikes in protest. It lasted 21 days. It is also worth noting that Gandhi had 14 such hunger strikes in his life.

Longest starving person

The longest starving person was a Scot who in 1965 decided to lose weight in a very drastic way. Under the supervision of physicians he starved himself for 1 year and 17 days. It was not a full-fledged starvation, because the patient received a small portion of yeast and a set of essential vitamins and minerals – a total of about 60 calories. However, even this small amount proved to be enough to keep the 27-year-old in good shape. After 382 days, Angus Barbieri had reduced his weight from 207 to 82 kilograms.

Starvation is also a religious ritual. The most extreme example is Sokushinbutsu which means self-mummification. Buddhist monks, for almost three years ate only nuts and seeds, while doing physical exercise. Then, for another three years, they fed on roots and herbs to induce poisoning of the body. In this way, the monks systematically supplied their bodies with ingredients that were used to embalm their future corpses. Finally, the monk was locked in a special cave, where he sat in the lotus position, awaiting death.

Starvation was also one of the methods of execution. However, it usually went hand in hand with a lack of water, so death was quicker – after just a few days.