What Happens When You Stop Eating?


If you are anything like me you probably have a love/hate relationship with food that begins with you attempting to watch your calories and ends up with you giving in to temptation, living with the guilt and/or spending hours at the gym trying to burn it off.

Well, today I decided to do something different. Today is the day to appreciate everything we eat; if not for the sake of its deliciousness, then for the simple fact that without it we cannot survive.

So what happens if we stop eating? I do not mean go on a three-day detoxification liquid only diet; I mean go completely without sustenance for an indefinite period of time—in other words, starve?

Well, this is not a simple question to answer. You see, the science of starvation is quite an enigma due to obvious ethical reasons; there is not a whole lot of credible scientific data on the topic of starvation and survival.

That being said, there are many cases of either voluntary or involuntary cases of complete or near-complete starvation; poor souls who got stranded in a desert or locked up without food, or hunger strikers with a message and a heart of gold.

Take Gandhi for example, known to have undergone up to 14 hunger strikes in his lifetime, one of which he underwent at the age of 74, for 21 days, with absolutely no food and survived. His, and the starvation accounts of many like him, allow us to make very general conclusions on the science of starvation.

Generally, it appears as though humans can survive without any food for 30−40 days, as long as they are properly hydrated. Severe symptoms of starvation begin around 35-40 days, and as highlighted by the hunger strikers of the Maze Prison in Belfast in the 1980s, death can occur at around 45 to 61 days, although some reports suggest that some people have survived for 70 days without eating anything.

The most common cause of death in these extreme cases of starvation is myocardial infarction or organ failure, and is suggested to occur most often when a person’s Body Mass Index (BMI)(1) reaches approximately 12.5 kg/m2. That would typically occur after the third stage of the metabolic process of starvation, after the body has been completely depleted of all fat storage as well as most muscle mass.

To know more about what happens during those stages, watch this video that highlights the three stages of starvation quite well:

So, How Does the Body Bo It?

In short, six hours after eating, the body has most likely gone through all of the glucose—body fuel—we ate; and we start feeling hungry and grumpy I might add as we now start relying on our glucose stores. These are rapidly depleted, but may last us a day or two; beyond that, our body will start using our fat—which on other occasions is grounds for celebration—as we enter ketosis(2) state.

The rough part happens after two to four days of no eating—this is the stage of autophagy. Once the fats are broken down, our body turns to breaking down protein in muscles, essentially wasting away our muscles. This can go on for up to three weeks or even 70 days, depending on every individual. Of course, how long we survive will depend on the amount of fat reserves we have; those that we normally do not appreciate.

For us, humans, food is not only a bare necessity for survival, but also a source of pleasure, and sometimes, health problems. It is wise then to watch what we eat, and make sure never to stop eating.


(1) The Body Mass Index (BMI), or Quetelet index, is a measure of relative size based on the mass and height of an individual. The index was devised by Adolphe Quetelet during the course of developing what he called “social physics”, between 1830 and 1850. The BMI for a person is defined as their body mass divided by the square of their height—with the value universally being given in units of kg/m2.

(2) Ketosis is a metabolic state where most of the body's energy supply comes from ketone bodies in the blood.


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