How long can someone survive without food?
The length of time a person can go without food depends on many factors, including age, biological gender, health, level of activity, and body fat.
Since the topic can not be studied ethically, finding quality research on the subject is difficult. One study did find a patient was able to go without food for 382 days, which is widely considered to be the longest recorded fast by a human.1 However, the patient had regular medical supervision (and IV fluids) throughout this experience, and this case is thought to be extreme or an outlier.
Other studies have looked at the experiences of people on hunger strikes. They discussed different types of fasts and how long humans can endure them, including:2
- Partial fasting: No solid food is consumed, but fluids, sugars, and nutrients are ingested
- Estimated survival time: Indefinitely, but with severe impacts on health
- Total fasting: Only fluids are consumed
- Estimated survival time: 2-3 months
- Dry fasting: No fluids nor solids are consumed
- Estimated survival time: Approximately 1 week
Another analysis concluded that biological women may withstand starvation longer than biological men, as their bodies generally carry more body fat and use it differently.4
Regardless of these specifics, once the body is deprived of food for long enough, it sets off a cascade of biological changes that can be difficult to reverse and have severe impacts on all levels of health.
You might be interested in
Fasting and the human body: What happens to the body without food?
The body requires a combination of proteins, sugars, fat, fiber, minerals, vitamins, and calories to function properly. It usually obtains these through food, but if someone is fasting or starving, the body must look elsewhere for what it needs.
As the body shuffles through these different sources of fuel, metabolism also changes, which impacts the way the body uses energy. Essentially, everything downshifts, allowing the body to maintain essential functions with less fuel.
A lowered metabolic rate can be extremely problematic, especially for sustained periods of time, and potentially lead to major organ failure and other severe health complications.5
Starvation phase I: Glucose
The body prefers sugars (glucose) as pure fuel. These are usually obtained from carbohydrates and other starchy foods. A properly fed body will use glucose to power the rest of its functions.
A fasting adult human body will generally run out of available glucose within 2-3 days of its last meal. This process is known as glycogenolysis or gluconeogenesis.6
Starvation phase II: Lipids
Once glucose sources are depleted, the body uses fats (lipids) for fuel.
Fat breakdown occurs in the liver in a process called ketogenesis. The supply usually comes from the fat already stored in the body. In fact, one of the major reasons the body has fat stores is to help with survival through periods of starvation.
Starvation phase III: Amino acids
Finally, in cases of prolonged starvation, the body begins breaking down muscle to use proteins (amino acids) for fuel. This phase of starvation can be extremely dangerous and lead to muscle loss and many other issues.
Sometimes referred to as protein wasting, this stage of starvation can become fatal once protein loss is over 50%.3
Symptoms of starvation
Symptoms of starvation can start out subtle but usually escalate rather quickly and can be especially visible once the body goes an extended period with very little food.
Some effects of starvation, long-term fasting, and/or severe hunger include:2,5,6,7
- Muscle wasting
- Hair loss
- Social withdrawal
- Weakened immune system
- Impaired emotional functioning
- Lowered sex drive
- Gastrointestinal issues
- Cold intolerance
- Impaired brain function, including:
- Alterations in consciousness
- Delusions
- Amnesia
- Psychotic episodes
- Renal (kidney) failure
- Dizziness
- Poor concentration
- Disrupted sleep
- Loss of body mass
Issues can quickly become severe and potentially life-threatening. And once someone has entered a phase of physical starvation, additional complications can arise from adding food back into their diet.
How to avoid refeeding syndrome after fasting
Refeeding syndrome is a dangerous and potentially deadly complication that occurs when someone who is starving or severely malnourished begins consuming more calories and nutrients.
Due to the metabolic changes that take place during starvation, consuming too many nutrients too quickly can cause major shifts within the body and lead to a dangerous imbalance of electrolytes, which can cause:8
- Trouble breathing or respiratory failure
- Double vision
- Seizures
- Coma
- Cardiac arrest or other heart complications
- Delirium
- Hypothermia
Due to the potential dangers involved, working with a medical treatment team during this period is highly important. Doctors can monitor the levels of various nutrients and electrolytes and manage refeeding to ensure a patient's body is getting what it needs and is not becoming overwhelmed by too much too fast.
The greatest risk period for refeeding syndrome is within 5 days of starting the refeeding process.8 If you or a loved one has been starved or severely malnourished, it's essential to seek out appropriate medical care to start your refeeding journey.
Finding help for an eating disorder
Intentional starvation is often a sign of an eating disorder or other mental health disturbance. If you or a loved one are intentionally limiting or eliminating food intake, it's crucial to seek out help. The effects of starvation can happen quickly, be severe, and be irreversible.
A number of treatments have been developed to address the very real mental and emotional issues that often work to drive these conditions. If starvation is serious enough, additional physical and nutritional treatment will likely be needed.
Speaking with a medical professional or licensed mental health practitioner can get the ball rolling. These professionals will likely be able to refer you to appropriate care centers or treatment programs. You can also explore the benefits of virtual eating disorder treatment through programs like Within.
Regardless of how you start your recovery journey, remember it's never too late. A healthier future is always possible.
.jpg)
%20THUMB.jpg)
