How Long Can You Survive Without Food? What Affects Survival

How Long Can You Survive Without Food What Affects Survival

For our bodies to survive, we need to eat and drink. Although there are cases of people surviving without food or drink for between 8 and 21 days, experts are unsure of the exact length of time that how long can you can go without eating.

These estimates are based on events where people have survived being trapped or buried alive, as it is not ethical to carry out such experiments on humans.

However, a person’s capacity for survival will vary depending on a number of variables, including their age, health, and access to water.

Please read on to find out how starvation influences the body, and how long can you go without water.

What Affects Survival

How long someone can go without eating can depend on a variety of factors, including sex, age, starting weight, and water intake.

Based on the scant amount of research that has been done on this topic. Scientists are unable to deliberately starve subjects in order to conduct this research for clear ethical reasons. Many people, however, focus on those who chose to starve themselves and were subsequently examined by a physician.

  • Sex: Compared to males, females live longer. Even in times of famine, this is true.
  • Age:During famines, children are more likely to die.
  • Starting weight: According to research, lean individuals can typically withstand a loss of up to 18% of their body mass before weakening after 30 to 50 days without food. Between 43 and 70 days is the typical death period. People who are obese, however, might be able to tolerate a loss of more than 20% of their body mass. For them as well, these timeframes are probably lengthy.
  • Water intake: In general, people who drink a lot of water can go longer without food.

How Starvation Influences the Body

Starvation has an impact on all of the body’s essential functions because food is these functions’ fuel.

Cardiovascular System

In order to make up for the lack of food, the body uses its own tissue as fuel. Heart muscle tissue may be a part of this process.

Because the heart lacks the fuel it needs to pump blood around the body as efficiently as it should, the pulse and blood pressure fall. Heart failure can result from this ineffective pumping.

Gastrointestinal System

The stomach’s ability to digest food and empty itself is hampered by food restriction. It can lead to:

  • bloating
  • stomach pain
  • vomiting
  • nausea
  • fluctuations in blood sugar levels
  • bacterial infections

Constipation can also result from chronically inadequate nutrition because it weakens the muscles in the intestines. The muscles may not have enough strength to force food that has been digested through the gut.

Pancreatitis, or inflammation of the pancreas, which causes discomfort, nauseousness, and vomiting, is another risk of starvation.

Central Nervous System

The brain, which can use up to 15% of a person’s energy, can be impacted by starvation. Lack of energy in the brain can cause problems with concentration and sleeping.

Endocrine System

The endocrine system needs fat and cholesterol to produce hormones like thyroid hormones, testosterone, and estrogen. Without them:

  • menstruation can become irregular or stop altogether
  • bones can weaken
  • metabolic rate can drop
  • core temperature can drop, leading to hypothermia

Dry skin, brittle hair, and hair loss are possible symptoms. The body produces lanugo, a downy layer of hair, in an effort to stay warm during times of starvation.

How Long Can You Survive Without Food What Affects Survival
How Long Can You Survive Without Food? What Affects Survival

How Long Can You Go Without Water?

Just like with food, it is difficult to pinpoint how long someone can live without water. While a healthy adult may survive for a few days, a child who has been left in a hot car by a parent or other adult may dehydrate and pass away within hours.

The exact amount of time that a person could survive varies depending on their unique body composition.

The body requires a constant flow of water to perform vital functions like cell maintenance and repair.

According to the Centers for Disease Control and Prevention (CDC), the symptoms of moderate dehydration are:

  • a dry mouth and tongue
  • restlessness and irritability
  • sunken eyes
  • feeling thirsty
  • urinating less

Severe dehydration can lead to:

  • lethargy
  • unconsciousness
  • a weak or absent pulse
  • a very dry mouth and tongue
  • low blood pressure
  • passing very little or no urine at all


For many reasons, not the least of which is that it is extremely dangerous, starvation is not a healthy way to lose weight.

When under starvation conditions, a person’s metabolic rate actually decreases, which results in less calorie burning. A wide range of health issues can be brought on by inadequate nutrition as a result of starvation.

Restrictive diets are very difficult to follow, so they usually aren’t very effective.

If someone wants to lose weight in a more long-term manner, they can speak with a doctor about this. A healthy diet and regular exercise are typically the cornerstones of an effective diet strategy.

Frequently Asked Questions

Will I Lose Muscle If I Go Without Eating?

Yes, but your body takes some time to start using muscle as a source of energy. The body will use up all of its fat and sugar reserves before using muscle. This might take a few days.

Can An Obese Person Go Without Food Longer Than a Normal-weight Person?

Research suggests that obese people may be able to fast longer than lean people before experiencing the negative effects of starvation.

When Will I Start Burning Fat If I Stop Eating?

After about 12 hours, your body will start using fat as fuel. After 16 to 24 hours without food, the process will move along much more quickly.

The Bottom Line

The human body is remarkably resilient. The body can occasionally go days or even weeks without the right nutrition and hydration. This is not to say that going without food for a long time is beneficial or risk-free.

Some people have reportedly been able to go up to a week without eating or drinking. In some circumstances, drinking water may help people survive longer.

Those who have been starved may experience long-term health effects. Eventually, if food is not reintroduced, starvation is fatal.

To prevent refeeding syndrome, people who have gone without food or been severely malnourished need to be closely watched by a doctor and medical staff.

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