There is a famine in the Gaza Strip. The Secretary General of the World Health Organization (WHO), Tedros Adhanom Ghebreyesus, spoke of “severe malnutrition” which has so far led to the deaths of ten children. The Hamas-run Ministry of Health speaks of at least 15 children who have died of malnutrition and dehydration.

An estimated 300,000 people in the northern Gaza Strip live without adequate food and clean water.

The body is programmed for survival

Prolonged hunger is an extreme strain on our bodies. But evolution has trained the human body to survive for weeks without food if necessary. People who are healthy and have enough water can survive for up to three months without food.

But that doesn’t work for everyone. If other factors such as diseases are present that further weaken the immune system, a person’s chances of survival are poor.

The brain knows the tricks

The hunger center in the hypothalamus plays a central roleThe metabolism center in the brain becomes active as soon as the blood sugar level drops. As a first step, this part of the brain ensures that the adrenal gland releases the stress hormone adrenaline. This allows the person to mobilize all of their strength to successfully search for food. If no food is supplied, the brain resorts to plan B.

To function, the brain needs glucose. Although the brain makes up only two percent of a person’s body mass, it uses about half of the body’s glucose consumption. So the brain uses a trick to secure all of the glucose reserves.

It works like this: Without insulin, glucose cannot reach the muscles. So the brain sends the signal to stop the release of insulin. The result: The muscles get nothing. The brain controls the metabolism so that it survives.

During periods of severe hunger, every organ shrinks to about half its original weight until death occurs. Not so the brain: It shrinks by a maximum of two to four percent. No wonder, then, that the brain secures the glucose reserves exclusively for itself.

If the food deprivation continues, the body resorts to protein for energy. This measure also comes at the expense of the muscles, which consist largely of protein. The body can produce glucose from finely chopped proteins, the amino acids.

Why you can smell hunger

After eight to ten days, the body switches its metabolism to a kind of energy-saving program: essential activities are reduced to a minimum: heart rate, blood pressure and body temperature drop – similar to an animal in hibernation. When there is little food available, this is the best the body can do.

The body also taps into its fat reserves. To do this, it converts fatty acids into so-called ketone bodies. These ketone bodies are an extremely important source of energy and make survival in times of hunger possible in the first place, because they are the only compounds that the brain can use besides glucose.

The fact that the metabolism of a starving person is resorting to fat deposits can sometimes even be smelled. The ketone bodies that are excreted via the kidneys and the breath include acetone, with its characteristic nail polish smell.

The longer the hunger lasts, the more negative consequences occur: the barrier function of the skin weakens, the immune system becomes weaker, and inflammation spreads.

When the organs fail

Little by little, the body draws brain nourishment from all vital organs. And after a while, the person is just skin and bones. The organs begin to fail. The heart is often the first to give up.

A person can only survive hunger for a long time if the metabolism – as described above – changes so that the brain can get by with less glucose. This makes it possible to maintain protein reserves in the vital organs. In order for all of this to work smoothly, the body must give an initial hunger signal. This stops the release of insulin. But that doesn’t always work.

For example, if someone suffers from malaria, AIDS or other diseases, they have so many inflammatory substances in their blood that the pancreas continues to secrete insulin. This in turn means that the starvation metabolism does not start.

Long-term effects of hunger

People recover from starvation. However, some struggle with long-term physical and psychological effects. These can include irreversible organ damage or dysfunction, impaired immune function, and loss of bone density.

Starvation can affect hormones such as insulin, cortisol and the thyroid gland. People who have starved are also often at higher risk of developing gastrointestinal problems. Starvation weakens the immune system and makes the body more susceptible to infectious diseases such as cholera, measles and malaria.

The consequences of famine are transmitted

Hunger is transmitted from mother to child. Malnourished pregnant women can pass the negative effects of hunger on to their babies.

In a 2022 study, researchers at Pennsylvania State University in the US examined people who were exposed to the “Dutch Hunger Winter,” a famine at the end of World War II. They wanted to examine the long-term effects of hunger on children. Across all age groups studied, the researchers found that malnutrition in the womb has serious health effects.

Babies born under such circumstances had an increased risk of diabetes, cardiovascular disease, obesity, musculoskeletal problems and hearing loss later in life.

The psychological effect of starvation

In the mid-1940s, researchers set out to analyze the physiology of starvation using an experiment that would be unthinkable today.

Under the leadership of American scientist Ancel Keys For three months, 36 test subjects received only half the calories they actually needed.

The psychological effects were particularly evident. Many participants withdrew and became apathetic. Hunger overshadowed everything. They were only interested in things that had to do with food. Some even dreamed of cannibalism. At the same time, their senses were extremely heightened: the test subjects were able to smell and hear much better than before the study began.

Quick help is needed

The studies are currently of little help to the people in Gaza. They urgently need help. Many of them are at acute risk of starvation. And aid organizations are often unable to even reach those in need. The widespread lack of food and clean water is a direct result of the barriers that aid organizations are encountering. According to UNICEF, people are hungry, exhausted and suffering from shock.

The brain controls the metabolism so that it survives. All other organs shrink to about half their original weight. Image: magicmine/Zoonar/picture alliance