Fasting

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Fasting is a willing abstinence or reduction from some or all food, drink, or both, for a period of time. An absolute fast or dry fasting is normally defined as abstinence from all food and liquid for a defined period, usually a period of 24 hours, or a number of days. Water fasting allows drinking water but nothing else. Other fasts may be partially restrictive, limiting only particular foods or substances. A fast may also be intermittent in nature. Fasting practices may preclude intercourse and other activities as well as food.

In a physiological context, fasting may refer to the metabolic status of a person who has not eaten overnight, or to the metabolic state achieved after complete digestion and absorption of a meal. Several metabolic adjustments occur during fasting, and some diagnostic tests are used to determine a fasting state. For example, a person is assumed to be fasting after 8-12 hours from their last meal. Metabolic changes toward the fasting state begin after absorption of a meal (typically 3-5 hours after a meal); "post-absorptive state" is synonymous with this usage, in contrast to the postprandial state of ongoing digestion.

A diagnostic fast refers to prolonged fasting (from 8-72 hours depending on age) conducted under observation for investigation of a problem, usually hypoglycemia. Many people may also fast as part of a medical procedure or check-up such as a colonoscopy.

Fasting is also a part of many religious rituals.

Video Fasting

Health effects

Medical application

Fasting is often practiced prior to surgery or other procedures that require general anesthesia because of the risk of pulmonary aspiration of gastric contents after induction of anesthesia (i.e., vomiting and inhaling the vomit, causing life-threatening aspiration pneumonia). Additionally, certain medical tests, such as cholesterol testing (lipid panel) or certain blood glucose measurements require fasting for several hours so that a baseline can be established. In the case of a lipid panel, failure to fast for a full 12 hours (including vitamins) will guarantee an elevated triglyceride measurement.

Cancer

Fasting is of no help in either preventing or treating cancer. In 2011, the American Cancer Society recommended that people undergoing chemotherapy increase their intake of protein and calories. There is weak evidence that a short-term period of fasting may have benefits during treatment.

Mental health and psychiatry

Fasting can help alleviate some symptoms of depression. However the psychological effects may also include anxiety and depression.

Immune system

Some scientists have indicated that a fast will cause white blood cells to break down during the fasting, resulting in new ones needing to be built when the fast is broken, resulting in the replacement of old damaged ones.

Weight loss

Although fasting for periods shorter than 24 hours have been shown to be effective for weight loss in obese and healthy adults, some researchers argue that using fasting for weight loss is unnecessary.

Fasts of short intervals (less than 24 hours) have been shown to reduce fat mass and maintain lean body mass.

Osteoporosis

Fasting is one of the alternatives proved to reduce the DPP-4 level and activate the Dipeptidyl peptidase 4 inhibitors and so, prevent osteoporosis.

Maps Fasting

Other effects

It has been argued that fasting makes one better appreciate food.

In rare occurrences, fasting can lead to refeeding syndrome.

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Political application

Fasting is often used as a tool to make a political statement, to protest, or to bring awareness to a cause. A hunger strike is a method of non-violent resistance in which participants fast as an act of political protest, or to provoke feelings of guilt, or to achieve a goal such as a policy change. A spiritual fast incorporates personal spiritual beliefs with the desire to express personal principles, sometimes in the context of a social injustice.

The political and religious leader Mohandas K. Gandhi undertook several long fasts as political and social protests. Gandhi's fasts had a significant impact on the British Raj and the Indian population generally.

In Northern Ireland in 1981, a prisoner, Bobby Sands, was part of the 1981 Irish hunger strike, protesting for better rights in prison. Sands had just been elected to the British Parliament and died after 66 days of not eating. His funeral was attended by 100,000 people and the strike ended only after 9 other men died. In all, ten men survived without food for 46 to 73 days.

César Chávez undertook a number of spiritual fasts, including a 25-day fast in 1968 promoting the principle of nonviolence, and a fast of 'thanksgiving and hope' to prepare for pre-arranged civil disobedience by farm workers. Chávez regarded a spiritual fast as "a personal spiritual transformation". Other progressive campaigns have adopted the tactic.

Yom Kippur Fasting: The Details | My Jewish Learning

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Religious views

Bahá'í Faith

In the Bahá'í Faith, fasting is observed from sunrise to sunset during the Bahá'í month of 'Ala' (March 1 or 2 - March 19 or 20). Bahá'u'lláh established the guidelines in the Kitáb-i-Aqdas. It is the complete abstaining from both food and drink during daylight hours (including abstaining from smoking). Consumption of prescribed medications is not restricted. Observing the fast is an individual obligation and is binding on Bahá'ís between 15 years (considered the age of maturity) and 70 years old. Exceptions to fasting include individuals younger than 15 or older than 70; those suffering illness; women who are pregnant, nursing, or menstruating; travellers who meet specific criteria; individuals whose profession involves heavy labor and those who are very sick, where fasting would be considered dangerous. For those involved in heavy labor, they are advised to eat in private and generally to have simpler or smaller meals than are normal.

Along with obligatory prayer, it is one of the greatest obligations of a Bahá'í. In the first half of the 20th century, Shoghi Effendi, explains: "It is essentially a period of meditation and prayer, of spiritual recuperation, during which the believer must strive to make the necessary readjustments in his inner life, and to refresh and reinvigorate the spiritual forces latent in his soul. Its significance and purpose are, therefore, fundamentally spiritual in character. Fasting is symbolic, and a reminder of abstinence from selfish and carnal desires."

Buddhism

Buddhist monks and nuns following the Vinaya rules commonly do not eat each day after the noon meal. This is not considered a fast but rather a disciplined regimen aiding in meditation and good health.

Once when the Buddha was touring in the region of Kasi together with a large sangha of monks he addressed them saying: I, monks, do not eat a meal in the evening. Not eating a meal in the evening I, monks, am aware of good health and of being without illness and of buoyancy and strength and living in comfort. Come, do you too, monks, not eat a meal in the evening. Not eating a meal in the evening you too, monks, will be aware of good health and..... living in comfort.

Fasting is practiced by lay Buddhists during times of intensive meditation, such as during a retreat. The Middle Path refers to avoiding extremes of indulgence on the one hand and self-mortification on the other. Prior to attaining Buddhahood, prince Siddhartha practiced a short regime of strict austerity--following years of serenity meditation under two teachers--during which he consumed very little food. These austerities with five other ascetics did not lead to progress in meditation, liberation (moksha), or the ultimate goal of nirvana. Henceforth, prince Siddhartha practiced moderation in eating which he later advocated for his disciples. However, on Uposatha days (roughly once a week) lay Buddhists are instructed to observe the eight precepts which includes refraining from eating after noon until the following morning. The eight precepts closely resemble the ten vinaya precepts for novice monks and nuns. The novice precepts are the same with an added prohibition against handling money.

The Vajrayana practice of Nyung Ne is based on the tantric practice of Chenrezig. It is said that Chenrezig appeared to an Indian nun who had contracted leprosy and was on the verge of death. Chenrezig taught her the method of Nyung Ne in which one keeps the eight precepts on the first day, then refrains from both food and water on the second. Although seemingly against the Middle Way, this practice is to experience the negative karma of both oneself and all other sentient beings and, as such is seen to be of benefit. Other self-inflicted harm is discouraged.

Christianity

The "acceptable fast" is discussed in the biblical Book of Isaiah, chapter 58:6-7. In this chapter, the nation of Israel is rebuked for their fasting, and given this exhortation:

This passage indicates that the acceptable fast is not merely abstinence from food or water, but a decision to fully obey God's commands to care for the poor and oppressed. Zechariah, chapter 7:5-10, also repeats this message. The opening chapter of the Book of Daniel, vv. 8-16, describes a partial Daniel Fast and its effects on the health of its observers.

Fasting is a practice in several Christian denominations or other churches. Some denominations do not practice it, considering it an external observance, but many individual believers choose to observe fasts at various times at their own behest. The Lenten fast observed in the Catholic Church and the Eastern Orthodox Church is a forty-day partial fast to commemorate the fast observed by Christ during his temptation in the desert. This is similar to the partial fasting within the Ethiopian Orthodox Church (abstaining from meat and milk) which takes place during certain times of the year and lasts for weeks.

Roman Catholicism

For Roman Catholics, fasting, taken as a technical term, is the reduction of one's intake of food to one full meal (which may not contain meat on Ash Wednesday and Fridays throughout Lent) and two small meals (known liturgically as collations, taken in the morning and the evening), both of which together should not equal the large meal. Eating solid food between meals is not permitted. Fasting is required of the faithful between the ages of 18 and 59 on specified days. Complete abstinence of meat for the day is required of those 14 and older. Partial abstinence prescribes that meat be taken only once during the course of the day. Meat is understood not to include fish or cold-blooded animals.

Pope Pius XII had initially relaxed some of the regulations concerning fasting in 1956. In 1966, Pope Paul VI in his apostolic constitution Paenitemini, changed the strictly regulated Roman Catholic fasting requirements. He recommended that fasting be appropriate to the local economic situation, and that all Catholics voluntarily fast and abstain. In the United States, there are only two obligatory days of fast - Ash Wednesday and Good Friday. The Fridays of Lent are days of abstinence: eating meat is not allowed. Pastoral teachings since 1966 have urged voluntary fasting during Lent and voluntary abstinence on the other Fridays of the year. The regulations concerning such activities do not apply when the ability to work or the health of a person would be negatively affected.

Prior to the changes made by Pius XII and Paul VI, fasting and abstinence were more strictly regulated. The church had prescribed that Roman Catholics observe fasting or abstinence on a number of days throughout the year.

In addition to the fasts mentioned above, Roman Catholics must also observe the Eucharistic Fast, which involves taking nothing but water and medicines into the body for one hour before receiving the Eucharist. The ancient practice was to fast from midnight until Mass that day, but as Masses after noon and in the evening became common, this was soon modified to fasting for three hours. Current law requires merely one hour of eucharistic fast, although some Roman Catholics still abide by the older rules.

Colloquially, fasting, abstinence, the Eucharistic Fast, and personal sacrificial disciplines (such as abnegation of sweets for Lent or the like) are altogether referred to as fasting.

The Catholic Church has also promoted a Black Fast, in which in addition to water, bread is consumed. Typically, this form of fasting was used only by monks and other religious individuals who practice mortifications and asceticism, but all Catholics are invited to take part in it with the advice and consent of their Spiritual Director.

Anglicanism

The Book of Common Prayer prescribes certain days as days for fasting and abstinence, "consisting of the 40 days of Lent, the ember days, the three rogation days (the Monday to Wednesday following the Sunday after Ascension Day), and all Fridays in the year (except Christmas, if it falls on a Friday)":

A Table of the Vigils, Fasts, and Days of Abstinence, to be Observed in the Year.

The eves (vigils) before:
The Nativity of our Lord.

The Purification of the Blessed Virgin Mary.

The Annunciation of the Blessed Virgin.

Easter Day.

Ascension Day.

Pentecost.

St. Matthias.

St. John Baptist.

St. Peter.

St. James.

St. Bartholomew.

St. Matthew.

St. Simon and St. Jude.

St. Andrew.

St. Thomas.

All Saints' Day.

Note: if any of these Feast-Days fall upon a Monday, then the Vigil or Fast-Day shall be kept upon the Saturday, and not upon the Sunday next before it.

Days of Fasting, or Abstinence.
I. The Forty Days of Lent.

II. The Ember-Days at the Four Seasons, being the Wednesday, Friday, and Saturday after the First Sunday in Lent, the Feast of Pentecost, September 14, and December 13.

III. The Three Rogation Days, being the Monday, Tuesday, and Wednesday, before Holy Thursday, or the Ascension of our Lord.

IV. All the Fridays in the Year, except Christmas Day.

Saint Augustine's Prayer Book defines "Fasting, usually meaning not more than a light breakfast, one full meal, and one half meal, on the forty days of Lent." Abstinence, according to Saint Augustine's Prayer Book, "means to refrain from some particular type of food or drink. One traditional expression of abstinence is to avoid meat on Fridays in Lent or through the entire year, except in the seasons of Christmas and Easter. It is common to undertake some particular act of abstinence during the entire season of Lent. This self-discipline may be helpful at other times, as an act of solidarity with those who are in need or as a bodily expression of prayer."

In the process of revising the Book of Common Prayer in various provinces of the Anglican Communion the specification of abstinence or fast for certain days has been retained. Generally Lent and Fridays are set aside, though Fridays during Christmastide and Eastertide are sometimes avoided. Often the Ember Days or Rogation Days are also specified, and the eves (vigils) of certain feasts.

Eastern Orthodoxy

For Eastern Orthodox Christians, fasting is an important spiritual discipline, found in both the Old Testament and the New, and is tied to the principle in Orthodox theology of the synergy between the body (Greek: soma) and the soul (pneuma). That is to say, Orthodox Christians do not see a dichotomy between the body and the soul but rather consider them as a united whole, and they believe that what happens to one affects the other (this is known as the psychosomatic union between the body and the soul). Saint Gregory Palamas argued that man's body is not an enemy but a partner and collaborator with the soul. Christ, by taking a human body at the Incarnation, has made the flesh an inexhaustible source of sanctification. This same concept is also found in the much earlier homilies of Saint Macarius the Great.

Fasting can take up a significant portion of the calendar year. The purpose of fasting is not to suffer, but according to Sacred Tradition to guard against gluttony and impure thoughts, deeds and words. Fasting must always be accompanied by increased prayer and almsgiving (donating to a local charity, or directly to the poor, depending on circumstances). To engage in fasting without them is considered useless or even spiritually harmful. To repent of one's sins and to reach out in love to others is part and parcel of true fasting.

Fast days

There are four fasting seasons, which include:

Great Lent (60 days) and Holy Week (7 days),
Nativity Fast (40 days),
Apostles' Fast (variable length), and
Dormition Fast (2 weeks)

Wednesdays and Fridays are also fast days throughout the year (with the exception of fast-free periods). In some Orthodox monasteries, Mondays are also observed as fast days (Mondays are dedicated to the Angels, and monasticism is called the "angelic life").

Other days occur which are always observed as fast days:

The paramony or Eve of Christmas and of Theophany (Epiphany)
Beheading of John the Baptist
Exaltation of the Cross

Rules

Fasting during these times includes abstention from:

oil (interpreted variously as abstention from olive oil only, or as abstention from all cooking oils in general), and
red wine (which is often interpreted as including all wine or alcoholic beverages)
sexual activity (where fasting is pre-communion)

When a feast day occurs on a fast day, the fast is often mitigated (lessened) to some degree (though meat and dairy are never consumed on any fast day). For example, the Feast of the Annunciation almost always occurs within the Great Lent in the Orthodox calendar: in this case fish (traditionally haddock fried in olive oil) is the main meal of the day.

There are two degrees of mitigation: allowance of wine and oil; and allowance of fish, wine and oil. The very young and very old, nursing mothers, the infirm, as well as those for whom fasting could endanger their health somehow, are exempt from the strictest fasting rules.

On weekdays of the first week of Great Lent, fasting is particularly severe, and many observe it by abstaining from all food for some period of time. According to strict observance, on the first five days (Monday through Friday) there are only two meals eaten, one on Wednesday and the other on Friday, both after the Presanctified Liturgy. Those who are unable to follow the strict observance may eat on Tuesday and Thursday (but not, if possible, on Monday) in the evening after Vespers, when they may take bread and water, or perhaps tea or fruit juice, but not a cooked meal. The same strict abstention is observed during Holy Week, except that a vegan meal with wine and oil is allowed on Great Thursday.

On Wednesday and Friday of the first week of Great Lent the meals which are taken consist of xerophagy (literally, "dry eating") i.e. boiled or raw vegetables, fruit, and nuts. In a number of monasteries, and in the homes of more devout laypeople, xerophagy is observed on every weekday (Monday through Friday) of Great Lent, except when wine and oil are allowed.

Those desiring to receive Holy Communion keep a total fast from all food and drink from midnight the night before (see Eucharistic discipline). The sole exception is the Communion offered at the Easter Sunday midnight liturgy, when all are expressly invited and encouraged to receive the Eucharist, regardless of whether they have kept the prescribed fast.

Fast-free days

During certain festal times the rules of fasting are done away with entirely, and everyone in the church is encouraged to feast with due moderation, even on Wednesday and Friday. Fast-free days are as follows:

Bright Week-the period from Pascha (Easter Sunday) through Thomas Sunday (the Sunday after Pascha), inclusive.
The Afterfeast of Pentecost-the period from Pentecost Sunday until the Sunday of All Saints, inclusive.
The period from the Nativity of the Lord until (but not including) the eve of the Theophany (Epiphany).
The day of Theophany.

Methodism

In Methodism, fasting is considered one of the Works of Piety. The Discipline of the Wesleyan Methodist Church required Methodists to fast on "the first Friday after New-Year's-day; after Lady-day; after Midsummer-day; and after Michaelmas-day." Historically, Methodist clergy are required to fast on Wednesdays, in remembrance of the betrayal of Christ, and on Fridays, in remembrance of His crucifixion and death. "The General Rules of the Methodist Church," written by the founder of Methodism, John Wesley, wrote that "It is expected of all who desire to continue in these societies that they should continue to evidence their desire of salvation, by attending upon all the ordinances of God, such are: the public worship of God; the ministry of the Word, either read or expounded; the Supper of the Lord; family and private prayer; searching the Scriptures; and fasting or abstinence." The Directions Given to Band Societies (25 December 1744) mandated fasting on all Fridays of the year. Wesley himself also fasted before receiving Holy Communion "for the purpose of focusing his attention on God," and asked other Methodist Christians to do the same. In accordance with Scripture and the teachings of the Church Fathers, fasting in Methodism is done "from morning until evening". The historic Methodist homilies regarding the Sermon on the Mount also stressed the importance of the Lenten fast. The United Methodist Church therefore states that:

There is a strong biblical base for fasting, particularly during the 40 days of Lent leading to the celebration of Easter. Jesus, as part of his spiritual preparation, went into the wilderness and fasted 40 days and 40 nights, according to the Gospels.

Rev. Jacqui King, the minister of Nu Faith Community United Methodist Church in Houston explained the philosophy of fasting during Lent as "I'm not skipping a meal because in place of that meal I'm actually dining with God".

Oriental Orthodox Churches

All Oriental Orthodox Churches practice fasting however the rules of each Church differ. All Churches require fasting before one receives Holy Communion. All Churches practice fasting on most Wednesday and Fridays throughout the year as well as observing many other days. Monks and nuns also observe additional fast days not required of the laity.

The Armenian Church (with the exception of the Armenian Patriarchate of Jerusalem) has followed the Gregorian Calendar since 1923, making it and the Finnish Orthodox Church the only Orthodox Churches to primarily celebrate Easter on the same date as Western Christianity. As a result, the Armenian Church's observation of Lent generally begins and ends before that of other Orthodox Churches.

With the exception of the fifty days following Easter in the Coptic Orthodox Church of Alexandria, fish is not allowed during Lent, or on Wednesdays, Fridays, and Paramon days. Other than that fish and shellfish are allowed during fasting days.

The discipline of fasting entails that, apart from Saturdays, Sundays, and holy feasts, one should keep a total fast from all food and drink from midnight the night before to a certain time in the day usually three o'clock in the afternoon (the hour Jesus died on the Cross). Also, it is preferred that one reduce one's daily intake of food (typically, by eating only one full meal a day).

The Eritrean Orthodox Tewahedo Church generally follows the fasting practices of the Coptic Church however in some cases it follows the Ethiopian Church.

The Ethiopian Orthodox Tewahedo Church has an especially rigorous fasting calendar.

Fasting in the Ethiopian Church implies abstention from food and drink. No animal products are consumed, including dairy, eggs and meat, and utensils that have touched such products must be washed before touching the strictly vegan foods that are consumed on fast days. During fast periods, Holy Liturgy (Mass) is held at noon (except on Saturdays and Sundays), and because no food can be consumed before communion, it is traditional for people to abstain from food until mass is over (around 2 to 3 in the afternoon). Every Wednesday and Friday are days of fasting because Wednesday is the day that the Lord was condemned and Friday is the day he was crucified (the Wednesdays and Fridays between Easter Sunday and Pentecost Sunday are an exception as well as when Christmas or Epiphany fall on a Wednesday or a Friday ). The fasts that are ordained in the canon of the Church of Ethiopia are:

1. Lent including Holy Week and the 10-day Fast of the Cross proclaimed by Byzantine Emperor Hereaclus (known as Hudadi, Abiye Tsom or Tsome Eyesus), 56 days.
2. Fast of the Apostles, 10-40 days, which the Apostles kept after they had received the Holy Spirit. It begins after Pentecost (known as Tsome Hwariat).
3. The fast of Assumption of the Holy Virgin, 16 days in August (known as Tsome Filseta).
4. Christmas Eve (Gahad ze Lidet) and The Eve of Epiphany, (Gahad ze Timket).
5. Advent, 40 days (Known as Tsome Gena that begin with "Sibket" on 15th Hedar and ends on Christmas Eve).
6. The fast of Nineveh, commemorating the preaching of Jonah. (On the Monday, Tuesday and Wednesday of the third week before Lent.
7. All Wednesdays and Fridays of the year except the ones that fall between Easter Sunday and Pentecost Sunday.

In addition to these, there is the fast of repentance which a person keeps after committing sin, it being imposed as a penance by the priest for seven days, forty days or one year. There is also a fast which a bishop keeps at the time he is consecrated. Also there are fasts that are widely observed but which have not been included in the canon of the church and which are therefore considered strictly optional such as the "Tsige Tsom" or Spring Fast, also known as "Kweskwam Tsom" which marks the exile of the Holy Family in Egypt.

All persons above the age of 13 are expected to observe the church fasts. Most children over age 7 are expected to observe at least the Fast of the Assumption of the Holy Virgin. Dispensations are granted to those who are ill.

The total number of fasting days amounts to about 250 a year. While many observe the Coptic Church's allowance for fish during the longer fasts, it has increasingly become practice in the Ethiopian Church to abstain from fish during all fasts according to the canons of the Ethiopian Church.

The observation of Lent within the Syriac Orthodox Church was once very strict but now is comparatively lenient compared with how it is observed in other Orthodox Churches.

Church of the East

The Assyrian Church of the East practices fasting during Lent, the seven weeks prior to Easter, wherein the faithful abstain from eating eggs, meat and any dairy or animal products. This is preceded by Somikka night.

The Church of the East strictly observes the Nineveh Fast (Som Baoutha). This annual observance occurs exactly 3 weeks before the start of Lent. This tradition has been practised by all Christians of Syriac traditions since the 6th century. At that time, a plague afflicted the region of Nineveh, modern-day northern Iraq. The plague devastated the city and the villages surrounding it, and out of desperation the people ran to their bishop to find a solution. The bishop sought help through the Scriptures and came upon the story of Jonah in the Old Testament. Upon reading the story, the bishop ordered a three-day fast to ask God for forgiveness. At the end of the three days, the plague had miraculously stopped, so on the fourth day the people rejoiced.

Lutheran and Reformed churches

In Protestantism, the continental reformers criticized fasting as a purely external observance that can never gain a person salvation. Martin Luther believed that a Christian may choose to fast individually as a spiritual exercise to discipline his own flesh, but that the time and manner of fasting should be left to the individual's discretion, thus he rejected the collective diet rules and prohibitions imposed by the canon law of the Catholic Church. This position was upheld by Lutheran churches, in that collective fasting was not officially enforced, whereas individual voluntary fasting was encouraged. John Calvin argued that instead of relying on designated fasting periods, the entire life of the religious should be "tempered with frugality and sobriety" in such a way as to produce "a sort of perpetual fasting". He believed that collective public fasting could be appropriate only in times of calamity and grief for the community. Similarly, the Swiss Reformation of the "Third Reformer" Huldrych Zwingli began with an ostentatious public sausage-eating during Lent--though Zwingli himself did not partake of the sausage.

In general, fasting remains optional in most Protestant groups and is less popular than among other Christian denominations. In more recent years, many churches affected by liturgical renewal movements have begun to encourage fasting as part of Lent and sometimes Advent, two penitential seasons of the liturgical year. Members of the Anabaptist movement generally fast in private. The practice is not regulated by ecclesiastic authority. Some other Protestants consider fasting, usually accompanied by prayer, to be an important part of their personal spiritual experience, apart from any liturgical tradition.

As explained above, the Lutheran Churches encourage individual fasting. Certain modern Lutheran communities also advocate fasting during designated times such as Lent. It is also considered to be an appropriate physical preparation for partaking of the Eucharist, but fasting is not necessary for receiving the sacrament. Martin Luther wrote in his Small Catechism "Fasting and bodily preparation are certainly fine outward training, but a person who has faith in these words, 'given for you' and 'shed for you for the forgiveness of sin' is really worthy and well prepared.".

Evangelicalism

Pentecostalism

Classical Pentecostalism does not have set days of abstinence and lent, but individuals in the movement may feel they are being directed by the Holy Spirit to undertake either short or extended fasts. Although Pentecostalism has not classified different types of fasting, certain writers within the movement have done so. Arthur Wallis writes about the "Normal Fast" in which pure water alone is consumed. The "Black Fast" in which nothing, not even water, is consumed is also mentioned. Dr. Curtis Ward points out that undertaking a black fast beyond three days may lead to dehydration, may irreparably damage the kidneys, and result in possible death. He further notes that nowhere in the New Testament is it recorded that anyone ever undertook a black fast beyond three days and that one should follow this biblical guideline. Dr. Herbert Shelton advises that one should drink water according to natural thirst. In addition to the Normal Fast and the Black Fast, some undertake what is referred to as the Daniel Fast (or Partial Fast) in which only one type of food (e.g., fruit or fruit and non-starchy vegetables) is consumed. In a Daniel Fast, meat is almost always avoided, in following the example of Daniel and his friends' refusal to eat the meat of Gentiles, which had been offered to idols and not slaughtered in a kosher manner. In some circles of Pentecostals, the term "fast" is simply used, and the decision to drink water is determined on an individual basis. In other circles profuse amounts of pure water is advised to be consumed during the fasting period to aid the cleansing of internal toxins. Most Pentecostal writers on fasting concur with Dr. Mark Mattson who says that sensible intermittent fasting with a sensible water intake can strengthen the organism and assist thwarting degenerative diseases.

Charismatic movement

For charismatic Christians fasting is undertaken at what is described as the leading of God. Fasting is done in order to seek a closer intimacy with God, as well as an act of petition. Some take up a regular fast of one or two days each week as a spiritual observance. Members of holiness movements, such as those started by John Wesley and George Whitefield, often practice such regular fasts as part of their regimen.

The Church of Jesus Christ of Latter-day Saints (Mormons)

For members of The Church of Jesus Christ of Latter-day Saints, fasting is total abstinence from food and drink accompanied by prayer. Members are encouraged to fast on the first Sunday of each month, designated as Fast Sunday. During Fast Sunday, members fast for two consecutive meals. The money saved by not having to purchase and prepare meals is donated to the church as a fast offering, which is then used to help people in need. Members are encouraged to donate more than just the minimal amount, and be as generous as possible. The late LDS President Gordon B. Hinckley asked: "Think ... of what would happen if the principles of fast day and the fast offering were observed throughout the world. The hungry would be fed, the naked clothed, the homeless sheltered. ... A new measure of concern and unselfishness would grow in the hearts of people everywhere." Fasting and the associated donations for use is assisting those in need, are an important principle as evidenced by Church leaders addresses on the subject during General Conferences of the Church, e.g. The blessing of a proper fast in 2004, Is Not This the Fast That I Have Chosen? in 2015

Sunday worship meetings on Fast Sunday include opportunities for church members to publicly bear testimony during the sacrament meeting portion, often referred to as fast and testimony meeting.

Fasting is also encouraged for members any time they desire to grow closer to God and to exercise self-mastery of spirit over body. Members may also implement personal, family or group fasts any time they desire to solicit special blessings from God, including health or comfort for themselves or others.

Hinduism

Fasting is a very integral part of the Hindu religion. Individuals observe different kinds of fasts based on personal beliefs and local customs. Some are listed below.

Some Hindus fast on certain days of the month such as Ekadasi, Pradosha, or Purnima.
Certain days of the week are also set aside for fasting depending on personal belief and favorite deity. For example, devotees of Shiva tend to fast on Mondays, while devotees of Vishnu tend to fast on Thursdays and devotees of Ayyappa tend to fast on Saturdays.
Tuesday fasting is common in southern India as well as northwestern India. In the south, it is believed that Tuesday is dedicated to Goddess Mariamman, a form of Goddess Shakti. Devotees eat before sunrise and drink only liquids between sunrise and sunset. In the North, Tuesday is dedicated to Lord Hanuman and devotees are allowed only to consume milk and fruit between sunrise and sunset.
Thursday fasting is common among the Hindus of northern India. On Thursdays, devotees listen to a story before opening their fast. On the Thursday fasters also worship Vrihaspati Mahadeva. They wear yellow clothes, and meals with yellow colour are preferred. Women worship the banana tree and water it. Food items are made with yellow-coloured ghee. Thursday is also dedicated to Guru and many Hindus who follow a guru will fast on this day.
Fasting during religious festivals is also very common. Common examples are Maha Shivaratri (Most people conduct a strict fast on Maha Shivratri, not even consuming a drop of water ), or the nine days of Navratri (which occurs twice a year in the months of April and October/November during Vijayadashami just before Diwali, as per the Hindu calendar). Karwa Chauth is a form of fasting practised in some parts of India where married women undertake a fast for the well-being, prosperity, and longevity of their husbands. The fast is broken after the wife views the moon through a sieve. In the fifth month (Shravan Maas) of the Hindu calendar, many celebrate Shraavana. During this time some will fast on the day of the week that is reserved for worship of their chosen god(s), while others will fast during the entire month.
In the state of Andhra Pradesh, the month of Kartik (month), which begins with the day after Deepavali is often a period of frequent (though not necessarily continuous) fasting for some people, especially women. Common occasions for fasting during this month include Mondays (for Lord Shiva), the full-moon day of Karthika and the occasion of Naagula Chaviti.

Methods of fasting also vary widely and cover a broad spectrum. If followed strictly, the person fasting does not partake any food or water from the previous day's sunset until 48 minutes after the following day's sunrise. Fasting can also mean limiting oneself to one meal during the day, abstaining from eating certain food types or eating only certain food types. In any case, the fasting person is not supposed to eat or even touch any animal products (i.e., meat, eggs) except dairy products. Amongst Hindus during fasting, starchy items such as Potatoes, Sago and Sweet potatoes are allowed. The other allowed food items include milk products, peanuts and fruits. It should be noted that peanuts and the starchy items mentioned above originate outside India.

In Shri Vidya, one is forbidden to fast because the Devi is within them, and starving would in return starve the god. The only exception in Srividya for fasting is on the anniversary of the day one's parents died.

Mahabharata:Anushasana Parva (Book 13)

Yudhishthira asks Bhishma, "what constitutes the highest penances?" Bheeshma states (in section 103) " ....there is no penance that is superior to abstention from food! In this connection is recited the ancient narrative of the discourse between Bhagiratha and the illustrious Brahman (the Grandsire of the Creation).

Bhagiratha says, The vow of fast was known to Indra. He kept it a secret but USANAS first made it known to the universe. Bhagiratha says, "In my opinion, there is no penance higher than fast." Bhagiratha did many sacrifices and gave gifts and says "the present that flowed from me were as copious as the stream of the Ganga herself.(but ..) it is not through the merits of these acts that I have attained this region." Bhagiratha observed the vow of fasting and reached "the region of Brahman"

Bheeshma advises Yudhishthira, "Do thou practice this vow (of fasting) of very superior merit that is not known to all."

In section 109, of the same book, Yudhishthira asks Bheesma "what is the highest, most beneficial" and fruitful "of all kinds of fasts in the world". Bheeshma says "fasting on the 12th day of the lunar month" and worship Krishna, for the whole year. Krishna is worshipped in twelve forms as Kesava, Narayana, Madhava, Govinda, Vishnu, the slayer of Madhu, who covered the universe in three steps, the dwarf (who beguiled Mahabali), Sridhara, Hrishikesha, Padmanabha, Damodara, Pundhariksha. and Upendra. After fasting, one must feed a number of brahmans. Bheeshma says " the illustrious Vishnu, that ancient being, has himself said that there is no fast that possesses merit superior to what attach to fast of this kind."

In section 106, of the same book, Yudhishthira says, "the disposition (of observing fasts) is seen in all orders of men including the very Mlechchhas..... What is the fruit that is earned in this world by the man that observes fasts?" Bheeshma replies that he had asked Angiras "the very same question that thou has asked me today." The illustrious Angiras says Brahmans and kshatriya should fast for three nights at a stretch is the maximum. A person who fasts on the eight and fourteenth day of the dark fortnight "becomes freed from maladies of all kinds and possessed of great energy."

Fasting for one meal every day during a lunar month gets various boons according to the month in which he fasts. For example, fasting for one meal every day during Margashirsha, "acquires great wealth and corn".

Vaishnavism

In some specific periods of time (like Caturmasya, Ekadashi fasting... ) it is said that one who fasts on these days and properly doing spiritual practice on these days like associating with devotees -sangha), chanting holy names of Hari (Vishnu, Narayana, Rama, Krishna...) (kirtanam) and similar (shravanam, kirtanam vishno...) may be delivered from sins.

Islam

Muslims believe that fasting is more than abstaining from food and drink. Fasting also includes abstaining from any falsehood in speech and action, abstaining from any ignorant and indecent speech, and from arguing, fighting, and having lustful thoughts. Therefore, fasting strengthens control of impulses and helps develop good behavior. During the sacred month of Ramadan, believers strive to purify body and soul and increase their taqwa (good deeds and God-consciousness). This purification of body and soul harmonizes the inner and outer spheres of an individual. Muslims aim to improve their body by reducing food intake and maintaining a healthier lifestyle. Overindulgence in food is discouraged and eating only enough to silence the pain of hunger is encouraged. Muslims believe they should be active, tending to all their commitments and never falling short of any duty. On a moral level, believers strive to attain the most virtuous characteristics and apply them to their daily situations. They try to show compassion, generosity and mercy to others, exercise patience, and control their anger. In essence, Muslims are trying to improve what they believe to be good moral character and habits.

Fasting is forbidden on these days:

Eid al-Fitr (1st Shawwal)
Tashriq (11th, 12th, 13th Dhulhijjah) in accordance with Sunni Islam.
Eid Al Adha (10th of Dhu al-Hijjah in the Hijri (Islamic calendar)). (Not necessarily the belief of all sects and schools of thought within the body of Shia Islam as various Shi'ite sects have opposing views)

Although fasting at Ramadan is fard (obligatory), exceptions are made for persons in particular circumstances:

Prepubescent children; though some parents will encourage their children to fast earlier for shorter periods, so the children get used to fasting.
Unconditional vomiting because the food leaves through an unintentional part of the gut.
Serious illness; the days lost to illness will have to be made up after recovery.
If one is traveling but one must make up any days missed upon arriving at one's destination.
A woman during her menstrual period; although she must count the days she missed and make them up later.
A woman till forty days after giving birth to child or miscarriage. But she must count the day she missed in Ramadan or they should donate the amount of a normal person's diet for each day missed to the poor or needy.
A woman who is pregnant or breast feeding. But she must count the day she missed in Ramadan or they should donate the amount of a normal person's diet for each day missed to the poor or needy.
An ill person or old person who is not physically able to fast. They should donate the amount of a normal person's diet for each day missed if they are financially capable.
A mentally ill person.
For elders who will not be able to fast, a lunch meal (or an equivalent amount of money) is to be donated to the poor or needy for each day of missed fasting.

Jainism

Fasting is very common among Jains and as a part of festivals.

Judaism

Fasting for Jews means completely abstaining from food and drink, including water. Traditionally observant Jews fast six days of the year. With the exception of Yom Kippur, fasting is never permitted on Shabbat, for the commandment of keeping Shabbat is biblically ordained and overrides the later rabbinically instituted fast days. (The optional minor fast of the Tenth of Tevet could also override the Shabbat, but the current calendar system prevents this from ever occurring.)

Yom Kippur is considered to be the most important day of the Jewish year-cycle and fasting as a means of repentance is expected of every Jewish man or woman above the age of bar mitzvah and bat mitzvah respectively. This is the only fast day mentioned in the Torah (Leviticus 23:26-32). It is so important to fast on this day, that only those who would be put in mortal danger by fasting are exempt, such as the ill or frail (endangering a life is against a core principle of Judaism). Those that do eat on this day are encouraged to eat as little as possible at a time and to avoid a full meal. For some, fasting on Yom Kippur is considered more important than the prayers of this holy day. If one fasts, even if one is at home in bed, one is considered as having participated in the full religious service.

The second major day of fasting is Tisha B'Av, the day approximately 2500 years ago on which the Babylonians destroyed the first Holy Temple in Jerusalem, as well as on which the Romans destroyed the second Holy Temple in Jerusalem about 2000 years ago, and later after the Bar Kokhba revolt when the Jews were banished from Jerusalem, the day of Tisha B'Av was the one allowed exception. Tisha B'Av ends a three-week mourning period beginning with the fast of the 17th of Tammuz. This is also the day when observant Jews remember the many tragedies which have befallen the Jewish people, including the Holocaust. The atmosphere of this fast is serious and deeply sad (in contrast to Yom Kippur which is a day of atonement).

Tisha B'Av and Yom Kippur are the major fasts and are observed from sunset to the following day's dusk. The remaining four fasts are considered minor and optional fasting is only observed from sunrise to dusk. Both men and women can choose to observe them, and a rabbi may give a dispensation if the fast represents too much of a hardship to a sick or weak person, or pregnant or nursing woman.

The four public but minor fast days are:

The Fast of Gedaliah on the day after Rosh Hashana
The Fast of the 10th of Tevet
The Fast of the 17th of Tammuz
The Fast of Esther, which takes place immediately before Purim

There are other minor customary fast days, but these are not universally observed, and they include:

"Bahab," (literally an acronym for "Monday, Thursday, Monday") the first two Mondays and first Thursday of the months Marcheshvan and Iyar (postponed by a week if Monday is the first of the month)
"Yom Kippur Katan," (literally "Little Yom Kippur") the day before every Rosh Chodesh, moved back to Thursday if that day is Saturday
The Fast of the Firstborn, on the day before Passover, which applies only to first-born sons; this obligation is usually avoided by participating in a siyum and ritual meal that takes precedence over fasting.

It is an Ashkenazic tradition for a bride and groom to fast on their wedding day before the ceremony as the day represents a personal Yom Kippur. In some congregations, repentance prayers that are said on Yom Kippur service are included by the bride and groom in their private prayers before the wedding ceremony.

Aside from these official days of fasting, Jews may take upon themselves personal or communal fasts, often to seek repentance in the face of tragedy or some impending calamity. For example, a fast is sometimes observed if a sefer torah is dropped. The length of the fast varies, and some Jews will reduce the length of the fast through tzedakah, or charitable acts. Mondays and Thursdays are considered especially auspicious days for fasting. Traditionally, one also fasted upon awakening from an unexpected bad dream although this tradition is rarely kept nowadays.

In the time of the Talmud, drought seems to have been a particularly frequent inspiration for fasts. In modern times as well the Israeli Chief Rabbinate has occasionally declared fasts in periods of drought.

Sikhism

Sikhism does not promote fasting except for medical reasons. The Sikh Gurus discourage the devotee from engaging in this ritual as it "brings no spiritual benefit to the person". The Sikh holy Scripture, Sri Guru Granth Sahib tell us: "Fasting, daily rituals, and austere self-discipline - those who keep the practice of these, are rewarded with less than a shell." (Guru Granth Sahib Ang 216).

Human mind requires wisdom, which can be achieved by contemplating on word's and evaluating it, torturing body is of no use: "He does not eat food; he tortures his body. Without the Guru's wisdom, he is not satisfied." (Guru Granth Sahib Ji, Ang 905)

If you keep fast, then do it a way so that you adopt the compassion, well being and ask for good will of everyone. "Let your mind be content, and be kind to all beings. In this way, your fast will be successful." (Guru Granth Sahib Ji, Ang 299)

Serve God who alone is your Savior instead indulge into ritual, he is only one who will save you every where: "I do not keep fasts, nor do I observe the month of Ramadaan. I serve only the One, who will protect me in the end. ||1||" (Guru Granth Sahib Ji, Ang 1136)

If you keep fast, to count everyday pledge yourself you will act honest, sincere, controls your desires, mediate. This is a way how you make yourself free of five thieves: "On the ninth day(naomi) of the month, make a vow to speak the Truth, and your sexual desire, anger and desire shall be eaten up. On the tenth day, regulate your ten doors; on the eleventh day, know that the Lord is One. On the twelfth day, the five thieves are subdued, and then, O Nanak, the mind is pleased and appeased. Observe such a fast as this, O Pandit, O religious scholar; of what use are all the other teachings? ||2||" (Guru Granth Sahib Ji, Ang 1245)

Goal of Human is to meet the Lord-groom, so Guru Sahib Ji says: "One who discards this grain, is practicing hypocrisy. She is neither a happy soul-bride, nor a widow. Those who claim in this world that they live on milk alone, secretly eat whole loads of food. ||3|| Without this grain, time does not pass in peace. Forsaking this grain, one does not meet the Lord of the World." (Guru Granth Sahib Ji, Ang 873)

"Fasting on Ekadashi, adoration of Thakurs (stones) one remains away from Hari engaged in the Maya and omens. Without the Guru's word in the company of Saints one does not get refuge no matter how good one looks." (Bhai Gurdas Ji, Vaar 7)

Taoism

The bigu (?? "avoiding grains") fasting practice originated as a Daoist technique for becoming a xian (? "transcendent; immortal"), and later became a Traditional Chinese medicine cure for the sanshi (?? "Three Corpses; the malevolent, life-shortening spirits that supposedly reside in the human body"). Chinese interpretations of avoiding gu "grains; cereals" have varied historically; meanings range from not eating particular foodstuffs such as food grain, Five Cereals (China), or staple food to not eating anything such as inedia, breatharianism, or aerophagia.

Yoga

In Yoga principle, it is recommended that one maintains a spiritual fast on a particular day each week (Monday or Thursday). A fast should also be maintained on the full moon day of each month. It is essential on the spiritual fasting day to not only to abstain from meals, but also to spend the whole day with a positive, spiritual attitude. On the fasting day, intake of solid food during the day is avoided and only a light veggie meal around 5 o'clock is taken. Water can be taken any time as needed. If health does not permit fasting for a whole day, for example with Diabetes, careful planning is done to reduce or skip one meal.

Other

The Bridegroom Fast - This fast was initiated by the leaders of the International House of Prayer, and is observed on the first Monday, Tuesday, and Wednesday of each month. Based on Matthew 9:15, its focus is intimacy with Christ, who is described in the Bible as the bridegroom of the Church. The fast is accompanied by services in Kansas City, which are freely accessible by webcast. It is observed largely in charismatic circles.
Jeûne genevois (lit. "fast of Geneva") is a public holiday and day of fasting in the canton of Geneva, Switzerland, occurring on the Thursday following the first Sunday of September.

Intermittent Fasting: A Fast Way To Lose Weight - IdealBite

src: idealbite.com

In alternative medicine

Since the mid 1970s alternative medicine has perpetuated ideas of "cleansing the body" through fasting.

Fasting and Asceticism | My Jewish Learning