Starvation

Starvation occurs when the body takes in far fewer calories than it needs to stay alive, making it the most severe kind of malnutrition. If it goes on for a long time, it can permanently damage organs and eventually kill a person. The physical and mental effects of starvation are known as inanition. Starvation can happen naturally or be caused by human actions. Intentionally starving a group of people is considered a crime under international law, and it can also be used as a method of torture or execution.

The World Health Organization calls hunger the single biggest threat to global public health. Malnutrition is the leading factor in child deaths, playing a role in half of all cases. Every year, undernutrition contributes to the deaths of 3.1 million children under five. While global hunger levels have evened out somewhat, and there has been progress in areas like reducing stunting and increasing exclusive breastfeeding, a troubling number of people still lack enough food. In fact, the world has regressed by about 15 years, with undernourishment rates matching those of 2008–2009. In 2023, between 713 and 757 million people were undernourished—over 152 million more than in 2019, when the midpoint was 733 million.

A swollen belly is a sign of a type of malnutrition called kwashiorkor. Exactly what causes kwashiorkor is not fully understood. It was once thought to come from a diet high in carbohydrates, like maize, but low in protein. Many patients have low levels of albumin, but this is now seen as a result of the condition, not the cause. Other possible triggers include aflatoxin poisoning, oxidative stress, problems with the immune system, and changes in gut bacteria. Treatment can ease symptoms like weight loss and muscle wasting, but preventing starvation in the first place is far more important.

Without any food, people usually die in about two months. One person survived for 382 days, but only under medical supervision. People who are lean can typically survive losing up to 18% of their body mass; those who are obese can lose more, sometimes over 20%. Women may live longer than men at the same body mass index because they tend to have more body fat.

The early stages of starvation affect a person’s mind and behavior. They may become irritable or unstable in mood, feel tired, have trouble concentrating, and think constantly about food. They are easily distracted and lack energy. Psychological effects are serious and include depression, anxiety, and reduced thinking ability.

As starvation gets worse, physical symptoms appear. How quickly this happens depends on a person’s age, size, and overall health, but it usually takes days to weeks. Symptoms include weakness, a fast heart rate, shallow and slow breathing, thirst, and constipation. Some people also get diarrhea. The eyes may sink in and look glassy. Muscles shrink and waste away. Tiredness and dizziness are common, especially during any physical activity. The skin often becomes very pale. In children, a swollen belly is a notable sign. The skin loosens and turns pale, and the feet and ankles may swell.

The immune system weakens, so wounds heal slowly and the body does not fight infections well. Rashes can develop on the skin. The body directs whatever nutrients it has to keep the vital organs working. Other effects include anemia, gallstones, low blood pressure, stomach disease, heart and lung problems, irregular or absent periods in women, and kidney disease or failure. Starvation can also cause hepatitis or reduced liver function, leading to electrolyte imbalance, extreme thinness, and reduced urine output.

The symptoms of starvation appear in three stages. The first two stages can happen to anyone who skips meals, diets, or fasts. The third stage is much more severe, can be fatal, and comes from long-term starvation.

In phase one, when meals are missed, the body keeps blood sugar levels steady by breaking down glycogen stored in the liver and using stored fat and protein. The liver can supply glucose for the first few hours. After that, the body starts breaking down fat and protein. Muscles use fatty acids for energy, but less glucose is sent to the brain. Glycerol, another substance from fatty acids, can be turned into glucose for energy, but it eventually runs out.

Phase two can last for weeks. During this time, the body mainly uses stored fat for energy. The liver breaks down fat into ketones. After about a week of fasting, the brain starts using these ketones along with any available glucose. Using ketones reduces the need for glucose, so the body slows down the breakdown of protein.

By phase three, fat stores are gone, and the body begins breaking down stored protein for energy. This means it has to break down muscle tissue, which is full of protein. Muscles break down very quickly. Protein is essential for cells to work properly, and when it runs out, cells can no longer function. The immediate cause of death from starvation is usually an infection or the result of tissue breaking down.