Table of contents:
- What happens to your body when you don't eat or drink at all
- 6 hours after last meal
- 3 days of not eating at all
- Don't eat for more than three days
- After 3 weeks of not eating
Humans can survive for three minutes without air. In an extremely extreme environment, for example, if you are trapped in the middle of nowhere on the mountains of Everest during a snowstorm, you have three hours to survive without shelter. Then, how long can humans survive if they don't eat and drink at all?
The duration of life without food is strongly influenced by a number of factors such as weight, genetic variation, other health considerations and most importantly, the presence or absence of dehydration. At 74 and slightly full, Mahatma Gandhi was able to survive 21 days of a total hunger strike (but drank several sips of water) in protest for Indian independence. Another hunger strike documented in world history saw survival success rates ranging from 46 hours to 70 days.
Although many factors are present in determining how long humans can live without food, our bodies go through certain metabolic processes which help us to conserve energy when food is not available within reach. Basically, the body buys time in search of nutrients. Here's about the chronology.
What happens to your body when you don't eat or drink at all
6 hours after last meal
This happens almost every day with most people. We eat, and then there's usually a few hours' pause before we eat again.
After eating, the body digests food to produce glucose - the main source of energy and is absorbed into the bloodstream. After 6 hours of walking without eating and drinking, our body will begin to break down body fat reserves to convert it into glucose and spread to cells and tissues through the bloodstream. About 25% of the energy produced is used solely for your brain, and the rest for muscles and red blood cells. The body's reserves of glucose can provide energy for you for 24-48 hours. At this stage, the brain's cognitive function will begin to decline as you increase the duration of your activities without eating and drinking.
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3 days of not eating at all
After 3 days without food, the fat stores are gone but the brain still needs glucose to function. Not only will you hungry all the time, but your body is also going into the ketosis stage. When the body doesn't have enough glucose from food to process into energy, fat is burned - which is then broken down into fatty acids. However, your brain cannot function solely from these fatty acids as a source of energy, so this in turn will interfere with normal brain function.
At this point, you will begin to have double vision and hallucinations. In order to stay "on", the brain will continue to use the remaining glucose stores in your body to the last drop, especially in the liver. This will provide about 30 percent of the energy for the brain. This is an important bodily adaptive response during starvation.
After 3 days, you will need water to survive or it will be your last day on earth.
Don't eat for more than three days
On the fourth day, your brain will get nearly 70 percent of the energy from the ketosis process. After 3 days, the spare fuel in the liver will be depleted. With only water to survive, our bodies basically feed on itself - known as autophagy.
Autophagy is the process of breaking down proteins in the body which will be used as fuel for all body systems. The protein that is broken down comes from the destruction of muscle tissue, which is one of the body's tissues that contains the most protein. Interestingly, the body will lose the most protein in the first 72 hours before the process slows down again to preserve the last energy supply. However, even though your brain will be able to survive solely on body protein, your muscles will slowly disappear.
ALSO READ: The Importance of Mindful Eating, Eating with Mindfulness
After 3 weeks of not eating
After 3 weeks of not eating, the body continues to look for sources of protein to convert into fuel. After the muscle is lost, the only source of energy left is the body's tissues and organs as the second largest protein store in the body. By breaking down the proteins of the body's tissues and organs, you may last up to three weeks or even up to 70 days, depending on whether you stay hydrated or have plenty of fat reserves to use for energy.
However, at some point, your immune system will start to shut down due to a lack of vitamins and minerals. Without a supply of vitamins or minerals, along with a "shutdown" of the immune system, "unnecessary" bodily functions, such as menstruation and libido, will also stop completely.
ALSO READ: 5 Vitamins You Need for a Healthy Liver
Usually, two diseases can occur in the final stages of starvation: marasmus and kwashiorkor. Marasmus is a severe form of malnutrition and energy deficiency, characterized by loss of muscle mass and edema, or flatulence. Kwashiorkor is the most common form of malnutrition in developing countries, caused by an inadequate intake of protein and also characterized by fatigue, edema, and decreased muscle mass.
If by some miracle you did not fall ill from extreme hunger, your body would slowly fall into a vegetative state - its biological function as a human being is still working, but your brain in general is no longer functioning - which is followed by death.
No, this doesn't mean you have to try it to prove it.
