Without water we can only survive a few days. However, we may be able to live for weeks without food. This is because the body is very resourceful. It is capable of obtaining energy and fuel from its own fat. If necessary, you can also use muscle reserves.
Still, the time for survival without food is not exact. There is no solid scientific evidence to answer this question. It’s basically because ethics prevents scientists from studying starving people. Also, each person is different. Personal factors such as starting weight can play a role.
Our bodies are also capable of surviving for days without water. But we can go days or sometimes weeks without eating due to adjustments in our metabolism and energy consumption.
When does the body feel hungry?
The elimination of food and water intake for a significant period of time is also known as starvation . The body may be subject to starvation after a day or two without food or water. At that point, the body begins to work differently to reduce the amount of energy it burns.
The body normally uses glucose, or sugar, as the main source of energy. When we don’t eat, glucose stores are depleted within a day. After a day without eating, the body releases a hormone called glucagon . This hormone tells the liver to make glucose. This glucose is primarily used to fuel the brain.
After two or three days, the body begins to break down fatty tissue . The muscles use the fatty acids created during this process as their main source of fuel. Fatty acids are also used to form ketones in the liver, which are another substance the body can use for energy. These are released into the bloodstream and when the brain uses them for fuel, it doesn’t need as much glucose.
Humans can survive without food because the liver can switch to ketone production. When fatty acid stores are depleted, the body switches to protein. You get protein by breaking down your muscles. As this breakdown accelerates, the body begins to lose heart, kidney, and liver function. This is what ultimately leads to death.
There are only limited studies on how long people can live without eating. There seem to be some factors that influence how long a person can live without eating.
One factor is a person’s starting weight . Lean people can generally tolerate a loss of up to 18% of their body mass. Obese people can tolerate more, possibly more than 20%. Research has found that people who are neither obese nor overweight become weaker after 30 to 50 days without eating. Death usually occurs between 43 and 70 days. In obese people, these times are likely to be longer.
There are some studies that explore old research on hunger, as well as examine more recent cases of hunger in the real world. These cases include hunger strikes, religious fasts and other situations.
These studies have uncovered several observations about hunger:
- The body can survive 8 to 21 days without food or water and up to two months if there is access to adequate water intake.
- Today’s hunger strikes have provided information about hunger. Several hunger strikes end after 21 to 40 days. These hunger strikes ended due to the severe and life-threatening symptoms experienced by the participants.
- There seems to be a certain “minimum” number on the body mass index (BMI) scale to survive. Men with a BMI of less than 13 and women with a BMI of less than 11 cannot survive.
- Those who are of normal weight will lose a higher percentage of their body weight and muscle tissue faster than those who are obese by starving in the first three days.
Also, other factors that may play a role in survival time are age (children die earlier) and gender (women survive longer).
Effects on the body
Being able to live for days and weeks without eating or drinking water seems inconceivable to many of us. After all, a day’s fast or even an hour’s stretch without food or water can leave many of us cranky and drained of energy.
The body really only adjusts if it engages in a short-term fast or is unable to access food and water for long periods of time. This allows people to participate in religious fasts and even try “fasting” diets, stop eating without causing irreparable damage to their bodies.
It takes about eight hours without eating for the body to change the way it works. Before that, it works as if we were eating normal. Under normal circumstances, the body breaks down food into glucose. Glucose provides energy to the body. Once the body has not had access to food for 8 to 12 hours, glucose stores are depleted. The body will begin to convert glycogen from the liver and muscles into glucose.
After glucose and glycogen are depleted, the body will begin to use amino acids to provide energy. This process will take a toll on the muscles and can keep the body going for three days of starvation before the metabolism makes a major shift to preserve lean body tissue.
To prevent excessive muscle loss, the body begins to rely on fat stores to create ketones for energy, a process known as ketosis . We will experience significant weight loss during this time. One of the reasons women can withstand starvation longer than men is that their bodies have a higher fat composition. Females are also able to hold on to protein and lean muscle tissue better than males during starvation.
The more fat reserves that are available, the longer a person can survive during starvation. Once fat stores have been fully metabolized, the body turns to breaking down muscle for energy, as it is the only source of fuel left in the body. We will begin to experience severe adverse symptoms during the starvation stage where the body uses muscle stores for energy.
Unless food intake is resumed, starvation always leads to death. Before death, certain complications may occur. The number of body systems affected increases as weight loss increases.
Some of these complications can be:
- bone loss
- Muscle weakness and wasting
- To feel cold
- Hair thinning or loss
- drop in blood pressure
- Abdominal pain
- Slowing of the heart rate
- Dry Skin
- Potassium deficiency
- In women, loss of menstruation
- Fatigue, shortness of breath, and paleness from anemia
Living without access to food and water can have detrimental effects on the body. Many body systems will begin to deteriorate despite your body’s ability to go on for days and weeks without food and water. Those who experience hunger for a long time cannot start consuming normal amounts of food right away. The body must return to eating very slowly to avoid adverse reactions, known as refeeding syndrome , such as heart disease, neurological conditions, or swelling of body tissue.
Returning to eating after starvation will require a doctor’s supervision and may involve eating boiled vegetables, lactose-free foods, and a diet low in protein and sugar.