How Long Can A Human Go Without Eating (And Why)?

How Long Can A Human Go Without Eating (And Why)?

Exact Answer: 8 To 21 Days

The need to eat is one of the most fundamental human needs. Many factors can lead to not getting food, but one needs to understand how long we can go without eating. 

A person may want to know how long they can last before feeling the effects, while another might be wondering if they could make it a week or more. 

This article will discuss how long humans can go without eating and what happens when they starve themselves without adequate water intake.

How Long Can A Human Go Without Eating

How Long Can A Human Go Without Eating?

Without Food2 Months
Without water and food8 to 21 days

In fasting studies on humans, it’s been shown that hunger becomes more manageable after three days. After day four of the study, some people lost weight, and fat levels increased. In a marathon, runners or athletes who do not eat for a week or longer, they’re attempting to lose weight to meet a specific goal. 

Eliminating food and water intake is starvation, and if it continues for a day or two, the body starts functioning differently, which eventually leads to death.

Some people believe it is an entire lifestyle change with implications for their food choices. In contrast, others use periods of fasting as a way of ‘cleansing the body from time to time by limiting what they eat and increasing their intake of drinks like fruit juices and coffee. 

One can go without eating for about 3 weeks before the body starts shutting itself down — but no one should have to try.

Many people thrive quite well on an intermittent fasting schedule, which means getting plenty of food within a designated time frame and then fast for set periods. This type of program is great for breaking unhealthy cycles related to high stress or sleep deprivation or other aspects that contribute to weight gain over the long term. The longest period someone could conceivably fast is 1-2 days, 30 days at most — other than risking death by malnutrition after 50-days without food; there would be risks associated with muscle breakdowns, kidney shutdowns, heart failure increasing steadily as one proceeds towards death.

Why Would A Human Go Without Eating For So Long?

A person could go without eating for so long if their body entered into a state of ketosis.

Ketosis is the metabolic state in which the liver produces ketones – molecules derived from fat capable of providing some cells with an alternative energy source. Roughly, signs of ketosis include Ketone urine/stool test, hunger during resting hours, nausea after food consumption, and weight loss.

 Detected Ketones consist mainly of acetoacetate and beta-hydroxybutyric acid with little to no acetone or Schumacher’s Acids occurring naturally in the bloodstream. 

It is, of course, a survival mechanism. When food supplies are scarce, and water is minimal, going without eating can help extend a person’s time to survive.

If the human body goes for over three months without fuel to save vital resources—namely water and fats—muscle wasting begins to occur. The reason it’s been identified as an evolutionary trait from animals that hibernate or winter sleep “is because there are documented cases of humans surviving up to 10 months without any sustenance whatsoever.”

The answer depends on the reason for going without eating. The peak of human performance is at around 8-hours after one has eaten, and the mental, physical, and emotional faculties decline fast with prolonged starvation.

Many people wonder how one can survive till 3 weeks without eating because one starts to feel irritable even with 8 hours of fasting. One can expect to have severe symptoms during starvation as the body uses muscles reserves for energy sources.


One might be surprised at how long they can go without food. It depends on their physical activity level, but it’s about 3 days before they start feeling the effects of starvation for most people. 

The human body is capable of going without food for a long period. However, it’s not recommended that one try to go on an extended fast to lose weight. Instead, focus on eating healthy foods and exercising regularly to maintain health while looking good.

It is a given that no one can survive very long without water as it makes up 75 percent of the body weight.


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Hi! I'm Nidhi.

Here at the EHL, it's all about delicious, easy recipes for casual entertaining. So come and join me at the beach, relax and enjoy the food.

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