Fasting

Fasting is the act of not eating, and sometimes not drinking. It can be a short time, like going through the night without food before breakfast, or it can be longer depending on why a person is fasting.

People sometimes fast as part of medical checks or procedures, like before a surgery or certain tests. Doctors might also ask a person to fast for a certain time to help check for health problems.

Fasting can also be part of religious traditions or special events, and some people choose to fast regularly as a way to manage their health or weight.

Health effects

See also: Starvation response, Intermittent fasting, Autophagy, and Fasting and longevity

Changing the pattern of when we eat, such as eating less on some days and more on others, can help improve heart health and blood markers in people who have a higher body weight or health conditions that affect metabolism.

Fasting is often done before surgeries or certain medical tests. This is because it helps prevent serious problems during anesthesia and gives doctors a clear picture of health markers like cholesterol and blood sugar levels.

Some studies suggest that fasting can improve alertness, mood, and feelings of well-being. It may also help with symptoms of depression and boost thinking skills.

There is little proof that skipping meals for less than a full day helps with lasting weight loss in people who are very overweight.

Long periods without food, lasting from several days to weeks, can cause the body to change how it uses energy. Early on, the body makes a special sugar for energy, but later it starts using a different source called ketones. During long fasting, important minerals in the body can drop low, which might cause health problems. Some people use special drinks to help keep these minerals balanced. Weight loss during long fasting is usually about half a kilogram each day during the first week and a little less each day after. Early weight loss often includes muscle, but later it includes more body fat.

There is no strong proof that fasting helps humans live longer.

Adverse effects

Refeeding syndrome

Main article: Refeeding syndrome

Refeeding syndrome is a problem that can happen when someone who has not eaten for a while starts eating again. When they eat too quickly or too much, their body can get an imbalance of important minerals like potassium, magnesium, and phosphate. This imbalance can cause serious health issues and needs careful medical attention.

Gallstones

Main article: Gallstone

Fasting may raise the chance of developing gallstones in some people. This happens because when there is no food to digest, the gallbladder does not move as much. The bile inside can become too strong, increasing the risk of gallstones, especially during quick weight loss.

Political application

Fasting is sometimes used to show support for a cause or to bring attention to an important issue. One way people do this is through a hunger strike, where they choose not to eat as a peaceful way to protest or to encourage changes in rules or policies.

Famous leaders like Gandhi have used fasting to make strong statements about fairness and justice. In 1981, a prisoner in Northern Ireland named Bobby Sands began a hunger strike to ask for better treatment in prison. Though many people joined him, the strike was very hard, and it ended after several people had fasted for many weeks.

American civil rights activist César Chávez also used fasting to support peaceful change and to prepare for important actions to help farm workers. He believed that fasting could help people grow in their beliefs and spirit.

Religious views

Main article: Religious fasting

Many religions include fasting as a way to show devotion. In Judaism, there are special days like Yom Kippur and Tisha B'av when people do not eat or drink for 25 hours. Other Jewish fasts last from dawn until sunset.

In Christianity, many people fast during a time called Lent, especially on Ash Wednesday and Good Friday. Some Christian groups also fast on certain days, like Wednesdays and Fridays, or during special times of the year.

Muslims fast during the month of Ramadan. They do not eat or drink from dawn until sunset. This is a religious duty for all Muslims who are able, except for children or those who are unable.

Other religions, like Hinduism and Buddhism, also include fasting as part of their practices. Some traditions have specific days or months when people fast.

In alternative medicine

Some people who practice alternative medicine say that fasting can "cleanse the body," but this idea of "detoxification" is not supported by strong science.

In the early 1900s, many writers who were part of the natural hygiene or New Thought movement talked about the benefits of fasting. One person, Linda Hazzard, made her patients fast so strictly that it caused health problems for many of them. In 1911, writer Upton Sinclair wrote a book called The Fasting Cure, where he made big claims that fasting could cure many diseases. However, doctors later said that long periods of fasting can be harmful.

Types of fasting

Main article: Religious fasting

Fasting can mean different things depending on the reason, method, or schedule used. Many religions have special times for fasting. For example, some people fast during Ramadan or Lent.

There are also different ways to fast, like only drinking water or juice, or going without food for a certain number of hours each day. Some people fast to help with health goals, while others might fast for short periods as part of a special diet.