Estimates indicate that starving people become weak in 30 to 50 days and die in 43 to 70 days. Individual factors including sex, age, starting weight, and water intake all play a role in how long someone can live without food. The body works to fight starvation by producing glucose and breaking down fatty tissue.
Muscles shrink and people feel weak. Body temperature drops and people can feel chilled. People can become irritable, and it becomes difficult to concentrate. Eventually, nothing is left for the body to scavenge except muscle.
Long-term fasting state (48+ hours)
Insulin levels slowly continue to drop2 during this phase, while ketone levels steadily increase. Ketones serve as the body's main source of energy, and the breakdown of amino acids (aka protein) from the muscle cells is reduced to help preserve muscle mass.
In addition to the potential weight loss benefits of doing 36 hour fasting once a week, the health benefits of fasting for 36 hours once a week can include the following: Reducing the risk of cardiovascular disease and coronary artery disease.
Longer periods without food, such as 24-, 36-, 48- and 72-hour fasting periods, are not necessarily better for you, and may be dangerous. Going too long without eating might actually encourage your body to start storing more fat in response to starvation.
If you stop eating and drinking, death can occur as early as a few days, though for most people, approximately ten days is the average. In rare instances, the process can take as long as several weeks.
The final stage of starvation includes signals like hair color loss, skin flaking, swelling in the extremities, and a bloated belly. Even though they may feel hunger, people in the final stage of starvation usually cannot eat enough food to recover.
The lack of pain is part of a protective mechanism developed over millions of years, Sullivan said. After 24 hours without food, “the body goes into a different mode, and you're not hungry anymore,” he said. “Total starvation is not painful or uncomfortable at all.
During starvation, the body first breaks down the proteins least essential for survival (e.g., some proteins in the liver and skeletal muscles) to provide the necessary amino acids. As a last resort, the body starts breaking down such proteins as those in the heart muscle.
It has been shown that your body temperature lowers when you don't consume enough calories. You feel lethargic. Without enough calories, you will quickly experience feelings of fatigue. Because your body doesn't have enough calories to burn and generate energy.
According to the USDA, there is a strong connection between hunger and chronic diseases like high blood pressure, heart disease, and diabetes. In fact, 58% of the households that receive food from the Feeding America network have one member with high blood pressure.
Altogether, it seems possible to survive without food and drink within a time span of 8 to 21 days. If a person is only deprived of food, the survival time may even go up to about two months, although this is influenced by many factors.
People can survive up to three weeks after they stop eating. However, without staying hydrated (without water) as well, the human body can only live 3 to 5 days. Researchers believe that a person can live for up to three weeks without food as long as they have water to drink.
Starving your body, whether consistently or inconsistently, can result in weight gain since your body is confused. Your metabolism is slowed so you're not burning through calories, or excess fat. Additionally, starving yourself can lead to fits of binge eating later, since you're so hungry.
If you go long enough without eating, you will use up the glucose in your system and then enter ketosis. During ketosis, your body switches to an alternative fuel source, ketones, which your body makes from fat. If you've ever been to a decent holiday party you've noticed that putting on fat is pretty easy.
After 3 days
Once you have gone 3 days without food you enter into what is known as the “starvation mode.” This is a process that the body uses to survive lack of nutrition. Fat stores are gone and the brain needs glucose to function. It begins to use the stores in the liver through a process called ketosis.
After two or three days without food, your body starts to break down fatty tissue. Your muscles use the fatty acids created during this process as their main source of fuel. Fatty acids are also used to form ketones in the liver. Ketones are another substance the body can use for energy.
If you don't eat for 10–16 hours, your body will go to its fat stores for energy, and fatty acids called ketones will be released into the bloodstream. This has been shown to protect memory and learning functionality, says Mattson, as well as slow disease processes in the brain.
The story of Angus Barbieri, who went 382 days without eating.
According to one study, you cannot survive for more than 8 to 21 days without food and water. Individuals on their deathbeds who use little energy may only last a few days or weeks without food or water. Water is far more important to the human body than food.
After three to five days of not drinking water, your organs begin to shut down, especially the brain, which could have lethal consequences including fainting, strokes and in extreme cases, even death.
The First Phase of Starvation
During the first stage of starvation, blood glucose levels are maintained through the production of glucose from proteins, glycogen and fats. At first, glycogen is broken down into glucose. Only enough glycogen; however, is stored in the person's liver to last a few hours.