How Long Can You Survive Without Food & Water? (Survival 101)

How Long Can You Survive Without Food & Water

If you should ever find yourself in a situation where there is a lack of food and fresh water, then you need to know how much time you will have left before you die of thirst or starvation.

Most humans will last 3-5 days without water and from 7-60 days without food depending on some factors that will shorten or lengthen the timespan.

In this article, I will cover everything from the bodily functions of water to the stages and symptoms of dehydration.

I will also include the factors that will determine the length of your starvation and the phases starvation usually goes through. I will also cover the symptoms of starvation and water fasting.

Let’s get started.

Water And Survival

Water plays a critical role in our bodies, and we cannot live without it. In this section, I am going to discuss how long our bodies can cope without water and some of the biological functions that water has in our bodies. I will also cover some of the symptoms of dehydration and what you can do to survive without water.

How Long Can We Survive Without Water?

survive without water

A normal human being can live for 3-5 days without water. Our bodies can go a long time without food because we have this natural and very primitive ability to store energy in the form of fat.

When it comes to water, we do not have this ability because our kidneys constantly regulate the water content of our bodies and if we have too much water, the kidneys will excrete most of it through urinating.

We need to drink around 2 liters of water per day to have a healthy balance of fluid in our bodies. Our body consists of 60% water to maintain normal bodily functions. There are also many factors that influence the number of days that you can go without water.

The rate in which you excrete water in the form of sweat and your body temperature plays a significant role in the amount of moisture that you will lose. People who do not experience any significant loss in moisture can go longer without water than those that need to sweat to counter hyperthermia.

Our normal body temperature is around 37 °C, and when it goes over 40 °C, then we enter a state of hyperthermia which can be deadly. When our body experiences this increase in temperature, it will then start to release fluids on the surface of our skin in the form of sweat.

Sweating allows our bodies to lose heat through evaporation. Our bodies can lose more than 1 liters of water per day in the form of sweat. If our temperature continues to increase, then we will suffer heat stroke.

Physical activity also increases the temperature of our bodies and is also a driving force for sweat and can shorten the duration for how long we can go without water. We need to drink around 2 liters of water per day to have a healthy balance of fluid in our bodies.

People that are also obese will lose more water because the subcutaneous fat will act as an insulator which will prevent most of the heat from escaping. Their bodies will sweat excessively trying to keep their temperature under control.

Bodily Functions That Depend On Water

Our body needs water and cannot go long without it. Water plays many crucial roles in our bodies which is why we need it. Below are some examples of some of the functions that water play to keep us alive and healthy.

Regulates the temperature of our bodies

Our bodies temperature needs to be regulated on an ongoing basis which is why we need systems in place which will do just that. If our temperature gets too high (over 40 °C), then we will suffer from hyperthermia. If it gets too low (below 35 °C), then we will suffer from hypothermia.

Water is used to produce sweat which helps to get rid of heat which contributes to hyperthermia. Sweat acts as a basis for evaporation which helps to get rid of the excessive heat in our bodies.

Keeps mucus membranes intact

Do you know what will happen to mucous membranes when they get dried out? They will start to crack, bleed and will not effectively do their job. Mucous membranes inside of our lungs help for oxygen and carbon dioxide to be transferred in and out of the body.

We also have mucous membranes in our sinuses and mouth to help with smell and digestion. Our eyes also have mucous membranes which need to be kept moisturized. Our digestive tract also has mucous membranes which aid in the digestion and absorption of nutrients.

Helps to get rid of toxins

Our bodies will try to get rid of toxins through our skin and urine. The skin also acts as one of our largest detoxification pathways, but it needs water to create the sweat required. You will notice that taking saunas will help your body to sweat to get rid of the toxins.

Our kidneys also help at filtering out our blood of any harmful toxins and will get rid of the toxins through our urine which also requires water. Water also helps our body at a cellular level to transport the toxins from within the cell to the extracellular fluid. Water also powers our lymph which is the fluid that circulates through the lymphatic system which also helps at transporting toxins and immune cells.

It lubricates our joints and protects our bodies

The water content in our bodies will help to keep our joints lubricated which will prevent any unnecessary wear and tear. We have around 360 joints in our body that need constant lubrication to function without causing harm.

Without this lubrication, our joint will work bone on bone which will create too much friction which ends in damage. Water in our bodies also acts as a natural shock absorber which will protect our organs from external stressors.

Aids in digestion and absorption

Our food needs to be digested before it can be absorbed. The first part of the digestive process happens in the mouth where we chew our food and the saliva which has the enzyme called amylase which breaks down starches. Our mucus also helps to form a bolus which can easily be swallowed. To form saliva, we need water.

Water also helps in the creation of stomach acid. Our stomachs manufacture this acid to break down complex food components into simpler components that our body can use. Stomach acid also helps to kill any harmful bacteria which might have entered our body through the mouth.

Water will also dissolve minerals and some nutrients which will make it easier for our digestive tract to absorb these components. Water also helps in the texture of our stool which is essential in preventing constipation.

Help to keep the blood thin

If we are dehydrated, our blood cells will become more concentrated which will make out blood thicker. If our blood becomes too thick, then it will struggle to move through the thinner capillaries to get oxygen and nutrients to those hard to reach places.

If the blood is too thick, then our circulation will slow down, and it will take longer for oxygen to reach our brain and other organs which will cause fatigue. If your blood is too thick, then you will also have lower energy levels.

Decreases the burden on our kidneys

It does not matter if our blood is thick or thin, it still needs to go through our kidneys. When our blood is thick, the amount of build up waist and acids which can then build up in our kidneys in the form of kidney stones. Dehydration is a leading cause of kidney failure and chronic kidney disease.

Symptoms Of Dehydration

The symptoms of dehydration can also be divided into phases or stages in which the body goes through to cope with the substantial water loss. Most people will at least experience the first stage in their lives while the advanced stage will require immediate medical attention and the final step can lead to death.

The stages of dehydration

The first stage

I can assume that most people have experienced the first stage of dehydration where they went without water for a whole day. The first stage is not so severe but can easily lead to the advanced stage which is not where you want to be.The symptoms of the first stage will include:

  • Dark urine
  • Dry mouth
  • Puffy and swollen eyes
  • Thirst
  • Fatigue
  • Dizziness
  • A headache

The dark urine is the reflection of the amount of water in your body as the waste products will be more concentrated in the urine. Your kidneys cannot afford to filter out too much water so it will have a dark yellow or orange color with a pungent odor.

Your eyes and mouth will become puffy and dry as your mucus membranes will start to dry out, crack and bleed. Our body’s natural response to dehydration is thirst as an early signal of dehydration. You will experience fatigue and dizziness as your blood will thicken which will cause your blood circulation to slow down which will give you less oxygen to the brain.

A headache is also a common sign as the blood struggles to go through the narrow capillaries in the brain causing pain.

The advanced stage

This stage is where things are starting to get serious. If you are experiencing this stage, then you want to get out of it as fast as possible as it can lead to irreversible organ damage and even death.The symptoms will include:

  • Very low or no urine output
  • Very low blood pressure
  • Very rapid heartbeat
  • Fever
  • Confusion

This can also be referred to as the second stage of dehydration. You will almost have no urine output as your kidneys do not want to waste any more water. Blood pressure will lower which will also cause dizziness when standing up.

Your heartbeat will become more rapid as it struggles to pump the thick blood throughout your body. You will also experience fever and a lot of confusion.

The final stage

When reaching this stage, it might be already too late. You need to seek out medical attention as soon as possible. This phase becomes a total body shut down.

  • Coma
  • Seizure
  • Shock
  • Vomiting and diarrhea

A coma might set in as your organs will start to shut down and a seizure might result from bursting blood vessels in your cranium while the brain contracts. Your body will also go into shock to cope with all of the stress and you might also experience vomiting and diarrhea to deal with the effect dehydration has on your digestive tract.

Survival Without Water

survival without water

If you should ever find yourself in a situation where you are in the middle of nowhere without any water, then it is essential to buy enough time for yourself so that you can wait for help. If you do not have access to water, then you need to limit the loss of moisture in your body. Below are some recommendations for if you should ever find yourself in such a situation.

Try to find fresh water

I have already written a guide on how to survive in the wilderness which includes methods that you can use to find and clean water. I have also dedicated an article on the desalination of water where you can make clean water from salt water.

If you are lucky enough to have access to a water stream or lake, then you should always cook the water first to kill all of the harmful bacteria. It is not worth getting diarrhea because it can lead to further dehydration.

Do not sweat too much

Depending on the location, you want to limit the amount of sweat your body produces to counter hyperthermia. If you are alone somewhere in a desert, you should only travel in the early mornings and later afternoons. Avoid too much movement during mid-day as this will lead to the most exhaustion and is too hot.

Do not be too active

The last thing that you want to do is to put too much physical stress on your body. If you burn too much energy, your body will produce heat which is a by-product of activity or you burning energy. You will start to sweat unnecessarily which is something that you can avoid.

Drink your own urine

Hopefully, you never need to be in a situation where drinking your own urine is your last resort. By doing this you will put in some extra fluid into your body, but you will also put in the wastes that your kidneys have filtered out.

Drinking your own urine is a short term solution to dehydration which might add an extra day to your survival. It is not a good idea to live off your urine which must be left as a last resort.

Cover yourself with thin white material

You would want to cover your face and neck as well as your body to protect yourself from sunburn. Make sure the material is light enough so that enough heat will escape from your body to prevent hyperthermia. You should also use white material because it will reflect most of the sun rays. Black material will absorb most of the sun rays which will make it hotter for you as it is.

Food And Survival

In this section, I am going to reveal to you the number of days which you can go without food and also the factors that will influence the duration of your starvation. I will also discuss the biological process that goes through your body after you stopped eating food and even the symptoms of starvation.

How Long You Can Go Without Food

eating food

In short, you can survive without food for a period of between 7 days up to 60 days. Unlike water, the body has the ability to store food/energy in the form of fat. Our ancestors did not have the luxury of storing food in freezers and other methods which include the preservatives that we use today.

So the bodies of our ancestors had to develop a way in which to store the energy that is consumed in excess to use in times of food scarcity. Today, people will also undergo religious fasts for up to a week with no negative health consequences.

It is also important to remember that there are several factors that will determine the duration of what it will take to survive without food. Factors such as fat deposits, activity and climate play a role in the duration.

The Factors That Will Determine The Duration Of Your Survival

There is no clear cut as to how long a human being can live without consuming food because there are several factors that will determine how long a person will last. It is also hard to conduct scientific studies because of the immorality of letting a subject starve.

A Fact is that some people can last several weeks longer without food than others. Below, I will discuss some of the contributing factors which will determine the length.

Your Fat Storage

I do not like to refer to “fat people” but the more subcutaneous fat you have stored, the longer you will last. The reason for this statement is that your body will start to burn the fat for fuel in a process called ketosis. Your body will keep using the fat for fuel until it is depleted.

Once the fat is gone, the body will then move onto muscle tissue to provide the energy needed for survival. Skinny individuals will have a hard time trying to survive without food for a prolonged period.

Your State Of Mind

Yup, you heard right. I have fasted under supervision for seven days straight while only drinking water. All I can say is that you need to be emotionally prepared for this process.

You will need to have a strong will to survive, and if you give up during the starvation process, you will most likely shorten the time to your death. Our subconscious mind can keep us alive during such dilemmas where our outcome will be dependent on the signals that we send to our body from our brain.

Your Water Intake

It was proved that the daily water intake could influence the length of how long you can survive without food. The reason behind this is not 100% clear, but if you do not drink enough water while not eating any food, you will drastically reduce the number of days you will survive.

If you are going on a fast, always remember to consume enough liquids. When I fasted, I did not drink enough, and I got a kidney stone which is extremely painful. There are a lot of events that take place in your body while starving to keep you alive and you do not want to jeopardize it with dehydration.

Certain diseases


Some diseases will make it worse for you if you are not able to eat food for a couple of days. If you have chronic kidney disease or diabetes, then you should not abstain yourself from consuming food. Other conditions such as gout can also become worse especially since your body will release a lot of acid during starvation.


Your climate also has a significant role to play in the number of days your body can go without food. If you live in freezing climates, then your body will need to produce extra heat to prevent hypothermia which takes extra energy to do.

Climates with very high temperatures are also not optimal as it will cause you to lose water in the form of sweat. It also puts unnecessary stress on your body.

Your Gender

Females also tend to last longer than males during starvation. The main reason for this is that they have less muscle mass which will require less energy and will store more reserves. More muscle mass requires more energy for maintenance.

Women’s bodies are adapted to store more energy in the form of fat in their bodies because they need to provide food for two people when they are in their gestation period.

Your metabolism

Your metabolism also works hand-in-hand with your fat storage. Metabolism can be defined as the process in which food is converted into energy. People with a fast metabolism will not last as long as people with a slow metabolism. People with a slow metabolism also needs to work harder and eat less to lose weight.

Your toxic burden

If your body is heavy with toxins, then you will have a hard time dealing with the release of them. Water fasting is one of the best ways to detox your body, where it will start to release the toxins in your cells to be filtered by your kidneys.

The problem with having a too high toxic burden is that it will be released at a very fast rate which your body will not be able to handle. This is the reason why you need to be in the right environment for detoxing such as drinking enough water and partaking in hydrotherapy to lessen the toxic burden on your kidneys and liver.

Your activity

Your physical activity is no-brainer when trying to survive starvation. Too much physical activity requires energy which is the last thing that you want to waste when trying to survive starvation or water fast. There is nothing wrong with taking a short walk, but you should not putt much stress on your body such as exercising or running.

Here Is What Happens Once You Stop Eating?

phases of starvation

There are specific changes that your body goes through once you stop eating. It takes about 8-14 hours for your body to adjust itself to survive without food.

Typically, our bodies will consume energy in the form of glucose which is the most accessible form of energy available. Most of the glucose will be stored in your blood, and it will not take for it to be used up. Your body will then switch to glycogen which is stored in your liver and muscles.

Remember that your body will not yet consume your muscle fibers during this stage but only some of the glycogen stored in the muscles. Once all of the glucose and glycogen is used up the body will move to the next source of available energy.

Next on the list is muscle protein. Your body will digest only a small part of your muscles into the available amino acids which your body can use. This process will happen for a day or two until your body will start to conserve your muscle mass and move to the next phase which is ketosis.

It takes around 1-3 days for your body to fully adjust to the fasting phase where it will successfully use your fat deposits instead of your muscles for energy. The more fat a person has, the longer he/she will last.

When your body has depleted your fat storage, then it will move to your muscles and organs which now can be defined as the starvation phase. You want to avoid this phase at all cost as the damage to your body will be irreversible.

Symptoms Of Starvation

 starvation symptoms

Below are some of the symptoms of starvation that you can look for. Some of the signs of starvation will be very obvious while others will be harder to detect.

  • Extreme weight loss
  • Dizziness
  • Brittle nails and weak hair
  • Fatigue
  • No menstruation
  • Depression
  • Extreme hunger

As your body enters starvation mode and starts to consume muscle protein for energy, then extreme weight loss is a system that can be easily detected. Dizziness is also a symptom but has more to do with low blood sugar levels.

Your nails and hair needs collagen for maintenance and growth and will become brittle and weak when you are starving. Your body will also experience fatigue when your body is saving energy to survive. In some cases, women will not have a menstrual cycle as their body is preventing reproduction.

Depression will also start to set in as the chemicals in the brain is out of balance. Hunger is too obvious but worth mentioning because your body is sending signals to your mind to consume food.

Water Fasting vs. Starvation

Before I start with this section, I would like to make it clear that if you should decide to do a water fast, that you seek the help from a licensed healthcare practitioner who will guide you through the process.

Let’s start with the fun stuff.

Starving and water fasting has the same principle behind them because the person that undergoes any of the two will abstain from eating any food in a given time. The time when a person starves is usually longer than when he is fasting.

What Is Water Fasting?

When fasting, you only drink clean and fresh water to hydrate your body for a given time. Before you fast, you need to make sure to undergo the miscarry tests to see if your body is capable of going without food and it can safely transition from using glucose to ketones (fat) as a fuel source.

You can also prepare your body by avoiding meat and only consuming food which is high in fat. The reason for this preparation is that you want to teach your body to look for fat as a fuel source and not muscle protein. When you eat meat before you undergo a fast, you will train your body how to use muscle tissue as a fuel source.

When water fasting, your body will mainly use fat as a fuel source and not muscle protein. It may use a little bit of muscle protein during the second day, but it will not last long. The doctor will also do a blood and urine test to see if your body is breaking down muscles and fat.

What Is Starvation?

Starvation is when your body has moved past the fasting phase and is now digesting your muscle tissue instead of fat. It will happen when most of your fat (reserves) is already used up and is now switching to muscle protein.

Sometimes our bodies will go straight to digesting muscle tissue and will leave your fat deposits alone. This is the reason why you would want to do a blood and a urine test to reveal which type of tissue your body is using. Your body will also start to show signs of mineral and vitamin depletion which are needed to sustain life.

The symptoms of starvation are also more severe than that of water fasting.

It’s Better To Be Prepared Than Dead

Hopefully, you will never need to go through starvation or severe dehydration anywhere in your life. Learn as much as possible from this blog so that you will know what to do if you are in a situation where you have no water or food. Go through these articles to better prepare yourself and acquire life-saving knowledge.

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