How long can modern man go without food?

It was advantageous for ancient man to stockpile nutrients. There were long periods of hunger, drought or hunting failed. Therefore, those who successfully stored fat and slowly expended energy had a better chance of survival. Thousands of years have passed, and living conditions for most of the population have changed dramatically. Unlike our ancestors, we, on the contrary, want to be slim – you can even trace how beauty standards have changed over the last few centuries. This begs the question: can we survive prolonged starvation without a fat “safety cushion”?

Medical Director of Lifetime+ Digital Labs

The entire history of humans, as well as other creatures of the animal kingdom, is about living on starvation. How many days of starvation is enough energy depends on the constitution and metabolism of the individual.

Nevertheless, it cannot be said that metabolism has not changed in any way during the history of mankind. For example, humans have lost the ability to produce vitamin C, and have not formed a mechanism for storing it. Sources of this substance in food became enough for a long time, so that evolutionary changes have had time to form. Vitamin C deficiency is possible only if for a long time a person’s diet is very poor in composition and there are no fresh fruits and vegetables in it.

Kirill: Such a diet was characteristic of seafarers of the era of great geographical discoveries – everyone has probably heard of scurvy, which crippled entire crews of ships. But sauerkraut and lemon juice made it possible to cope with the problem. And the inability to produce vitamin C was no longer a factor of natural selection. Everything that we lose the ability to do, but that does not cause death over many generations, spreads in the population and becomes characteristic of the species as a whole.

The human body undergoes changes similar to those of animals when they hibernate. If glycogen reserves run out, the body begins to consume proteins of its own tissue, processing them into glucose. In this case, the muscles suffer. Therefore, in the process of starvation, almost all organs lose approximately one third of their weight, and the brain is reduced by only 2-4%. At the same time, a person begins to spend his fat reserves.

doctor of clinical laboratory diagnostics, medical director of CITILAB

In the process of fat burning (another universal source of energy), ketone bodies are formed. This process is accompanied by the release of a certain odor, and a person begins to smell like acetone or nail polish (ketone bodies are also called acetone bodies). This stage is already considered life-threatening: irreversible processes of destruction of the body begin. The skin loses its protective properties, bones become brittle, immunity falls. The last source of muscle tissue in the body is the heart, after this stage death is inevitable.

How many days can a modern person live without food?

There is no unified data, although experts suggest that a person can live without food for about two months. Of course, no one has conducted scientific experiments. How many days of hunger will be enough energy depends on the constitution and metabolism of a particular person. On average, the daily requirement of the body is 2700 kcal. One gram of fat is 9 kcal, i.e. 300 grams of fat from internal reserves will need to be broken down during the day. The question is how big they are. On average, women have up to 25% of their body weight in fat, while men have up to 15%. If a man weighs 70 kg, he will have about 10 kg of fat, which is about 35 daily requirements. It is impossible to break down everything to zero, so it will be enough for a maximum of four weeks.

The source of energy will be not only fatty fiber, but also muscle tissue. The body uses it when there is little fatty fiber left. But a person dies not only from lack of energy, but also from lack of protein, which keeps fluid in the vascular bed. Without protein, it will flow into the tissues – in this case, edema will appear, blood pressure will begin to fall and eventually the heart will stop.

Prolonged starvation depletes vitamins, minerals, destroys the immune system and psyche. This contributes to the development of associated diseases that lead to death faster than the depletion itself. Starvation “kills” the microflora, thereby depriving another protective barrier. During this period, vitamin B1 and thiamine deficiency is especially dangerous. This leads to loss of vision, impaired thinking. Lack of vitamin C causes scurvy – a disease in which the gums bleed, teeth fall out, blood vessels easily burst.

Toxicologist, Professor, Academician of EAEN

Our environment has changed a lot during the long process of human evolution. At the same time, the rate of metabolism, the processes of utilization and excretion of decay products have slowed down. People in the past could survive without food for quite a long time thanks to adaptive mechanisms. In modern humans, they are much weaker, even though life expectancy has increased. Given the abundance of food from childhood, we are unable to endure prolonged hunger.