How long can you go without food and water?

With a spread like this, who'd want to go without food at all?
©iStockphoto.com/Jack Puccio

You sit in your cubicle like a zombie and pretend to look over expense reports. Your stomach growls like a cornered dog. As a test of will and determination, and because you have nothing better to do, you watch the noon hour pass with no lunch. One o'clock, you're feeling dizzy. Two o'clock, you're in a cold sweat. Three o'clock, you're under your desk in the fetal position, sucking your thumb. Finally, you give up and head for the break room to chow on a co-worker's leftover lo-mein. You down a gallon of water like a land-bound carp and finish your day in the bathroom.

At work, you may think you can't go more than a few hours without food and water. Sitting in a discount office chair in your cubicle is certainly no way to test your limits. There are many factors that go into how long a human can survive without food and water, and the will to do so is one of them. Going without water isn't smart, and it doesn't take long before you're suffering from dehydration. Food is a different story. Humans can go quite a long time without food as long as they're well hydrated. Your body weight, overall health and the weather play into the scenario as well. So the answer to the question isn't easy and depends on the person and the situation.

In this article, we'll take a good look at these factors and what might happen to your body if you go without either. We'll also learn some incredible stories of people that defied the odds without a crumb or drop.

Living Without Food

Indian leader Mohandas K. Gandhi, sitting on a mattress on the floor, surrounded by people at the end of his last fast.
Indian leader Mohandas K. Gandhi, sitting on a mattress on the floor, surrounded by people at the end of his last fast.
Margaret Bourke-White/Stringer/Getty Images

The question of how long you can go without food depends on a lot of factors. Will and determination definitely play a part. Political prisoners on hunger strikes and fasting religious leaders have been known to go for weeks at a time without any food. Gandhi fasted for 21 days while in his 70s. People lost in the wild have also survived for long periods of time without eating.

Medically speaking, most doctors agree that healthy humans can go up to eight weeks without food as long as they have water. People have gone longer and been fine, and people have starved to death in less time. Being strong and in good physical shape can help you survive longer, but so does having extra body fat. The body stores energy needed to live in the form of fat, carbohydrates and proteins. The carbs are the first thing to be used up without more food coming in. The fat goes next, which explains why people with more of it can survive longer. Then the proteins go. If you get to the point that your body is using up proteins, basically the body itself, then you're in bad shape.

Your metabolism also plays a role. Metabolism is what converts food into energy. If you have a slow metabolism, you'll burn your food intake slower and be able to go longer without replacing the food energy. If you go without food, your metabolism will adjust accordingly and slow down on its own -- basically doing what it can to pitch in for survival's sake.

Climate is a major factor too. The bad news is that both cold and hot weather are no good if you have no food. The good news is that extreme heat and cold will kill you in other ways before you have a chance at starvation. But in terms of living without food, heat means faster dehydration -- cold means more energy is burned to keep the body's temperature at a cozy 98.6 degrees Fahrenheit (37 degrees Celsius). If you're lucky enough to be in mild temperatures, you'll be able to live a little longer without food.

Some symptoms you may see if you go more than a couple of days without food are:

  • Weakness
  • Confusion
  • Chronic diarrhea
  • Irritability
  • Bad decision making
  • Decreased sex drive
  • Immune deficiency

Advanced starvation will cause your organs to shut down one by one. People in the throes of severe starvation might experience the following:

  • Hallucinations
  • Convulsions
  • Muscle spasms
  • Irregular heartbeat

In the next section, we'll look at how important water is and what happens to your body without it.

Living Without Water

Now that we've established that food is something we can do without for a reasonable amount of time, we can move on to water. Living without water is very different from living without food. In hot conditions with no water, dehydration can set in within an hour. A baby locked in a hot car or someone who is physically overexerted in the heat without replacing fluids can actually die in a period of several hours.

Humans need water to live, plain and simple. We lose water through sweat, urine, feces and even breathing. This water needs to be replaced in order for our organs to continue to work properly. In severe heat, an adult can lose as much as 1.5 liters of water through sweat alone [source: Scientific American]. The main risk without water in high heat is that your body temperature will continue to rise and you'll suffer from heat stroke. Drinking water will cool you down and lower your core temperature.

With mild dehydration, you'll experience the following:

  • Lack of saliva
  • Decreased frequency of urine
  • Decreased output of urine
  • Deep color and strong odor in urine

Moderate dehydration:

  • Even less urine
  • Dry mouth
  • Dry and sunken eyes
  • Rapid heartbeat

Severe dehydration:

  • No urine
  • Lethargy and irritability
  • Vomiting and diarrhea

The final stage of dehydration is shock. This is characterized by blue-gray skin that's cold to the touch. A severe drop in blood pressure produces this coolness.

Now back to the question at hand. How long can you go without water? Assuming you're in reasonable shape and in ideal conditions -- that is, not in the heat or cold and not exerting, a human can probably live for about 3 to 5 days without any water. Healthier humans can live another day or so longer.

This isn't something you should test. While people may fast or try a body cleanse without food, you should absolutely never go without water for more than a day. The Mayo Clinic recommends drinking about eight cups of water a day, although there's some debate about this number [source: Mayo Clinic]. Some physicians say less is fine, while others say the number should be closer to 10 cups or even more.

For more information on food, water and survival, please dive into the material on the following page.

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Sources

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  • "Irish Hunger Strike 1981." Irishhungerstrike.com, 2008. http://www.irishhungerstrike.com/
  • "Japanese man in mystery survival." BBC, December 21, 2006. http://news.bbc.co.uk/2/hi/asia-pacific/6197339.stm
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  • Mayo Clinic Staff. "Water: how much should you drink every day?" Mayo Clinic. May 23, 2006. http://www.mayoclinic.com/health/water/NU00283
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  • Sosa, Ninette; Franken, Bob; Phillips, Rich and Candiotti, Susan. "Terri Schiavo has died." cnn.com, March 31, 2005. http://www.cnn.com/2005/LAW/03/31/schiavo/index.html
  • "Water." uconn.edu, December, 2001. http://www.team.uconn.edu/15%20nfs%20kidswater.pdf