Fasting


Fasting is the willful refrainment from eating for a period of time. 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. Some diagnostic tests are used to determine a fasting state. For example, a person is assumed to be fasting once 8–12 hours have elapsed since the last meal. Metabolic changes of the fasting state begin after absorption of a meal.
A diagnostic fast refers to prolonged fasting from 1 to 100 hours conducted under observation to facilitate the investigation of a health complication, usually hypoglycemia. Many people may also fast as part of a medical procedure or a check-up, such as preceding a colonoscopy or surgery. Fasting may also be part of a religious ritual.

Health effects

Medical application

Fasting is always 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. Additionally, certain medical tests, such as cholesterol testing 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 will guarantee an elevated triglyceride measurement.

Mental health

In one review, fasting improved alertness, mood, and subjective feelings of well-being, possibly improving overall symptoms of depression.

Weight loss

Fasting for periods shorter than 24 hours has been shown to be effective for weight loss in obese and healthy adults and to maintain lean body mass.

Complications

In rare occurrences, fasting can lead to the potentially fatal refeeding syndrome upon reinstatement of food intake due to electrolyte imbalance.

Historical medical studies

Fasting was historically studied on population under famine and hunger strikes, which led to the alternative name of "starvation diet", as a diet with 0 calories intake per day.

Other effects

It has been argued that fasting makes one more appreciative of food.

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 nine 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.
According to an anonymous Uyghur local government employee quoted in a Radio Free Asia article, during Ramadan 2020, residents of Makit County, Kashgar Prefecture, Xinjiang, China were told they could face punishment for fasting including being sent to a re-education camp.

Religious views

Bahá'í faith

In the Bahá'í Faith, fasting is observed from sunrise to sunset during the Bahá'í month of 'Ala'. Bahá'u'lláh established the guidelines in the Kitáb-i-Aqdas. It is the complete abstaining from both food and drink during daylight hours. Consumption of prescribed medications is not restricted. Observing the fast is an individual obligation and is binding on Bahá'ís between 15 years 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

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.
Fasting is practiced by lay Buddhists during times of intensive meditation, such as during a retreat. During periods of fasting, followers completely stray away from eating animal products, although they do allow consumption of milk. Furthermore, they also avoid eating processed foods and the five pungent foods which are: garlic, welsh onion, wild garlic, garlic chives , and asafoetida. 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 and following years of serenity meditation under two teachers which he consumed very little food. These austerities with five other ascetics did not lead to progress in meditation, liberation, or the ultimate goal of nirvana. Henceforth, prince Siddhartha practiced moderation in eating which he later advocated for his disciples. However, on Uposatha days 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

Fasting is a practice in several Christian denominations and is done both collectively during certain seasons of the liturgical calendar, or individually as a believer feels led by the Holy Spirit; many Christians also fast before receiving Holy Communion. In Western Christianity, the Lenten fast is observed by many communicants of the Catholic Church, Lutheran Churches, Methodist Churches, Reformed Churches, Anglican Communion, and the Western Orthodox Churches and is a forty-day partial fast to commemorate the fast observed by Christ during his temptation in the desert. While some Western Christians observe the Lenten fast in its entirety, Ash Wednesday and Good Friday are nowadays emphasized by Western Christian denominations as the normative days of fasting within the Lenten season.
In the traditional Black Fast, the observant abstains from food for a whole day until the evening, and at sunset, traditionally breaks the fast. In India and Pakistan, many Christians continue to observe the Black Fast on Ash Wednesday and Good Friday, with some fasting in this manner throughout the whole season of Lent.
Partial fasting within the Ethiopian Orthodox Church which takes place during certain times of the year and lasts for weeks.

Catholicism

For Catholics, fasting, taken as a technical term, is the reduction of one's intake of food to one full meal and two small meals, 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 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 Catholics observe fasting or abstinence on a number of days throughout the year.
In addition to the fasts mentioned above, 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 Catholics still abide by the older rules.
Colloquially, fasting, abstinence, the Eucharistic Fast, and personal sacrificial disciplines such as abnegation of sweets for Lent 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, and all Fridays in the year ":

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

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 of certain feasts.
In addition to these days of fasting, Anglicans also observe the Eucharistic Fast. Saint Augustine's Prayer Book states that the Eucharistic Fast is a "strict fast from both food and drink from midnight" that is done in "in order to receive the Blessed Sacrament as the first food of the day" in "homage to our Lord". It implores Anglicans to fast for some hours before the Midnight Mass of Christmas Eve, the first liturgy of Christmastide.

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 and the soul. 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. 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. 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:
Wednesdays and Fridays are also fast days throughout the year. In some Orthodox monasteries, Mondays are also observed as fast days.
Other days occur which are always observed as fast days:
Fasting during these times includes abstention from:
When a feast day occurs on a fast day, the fast is often mitigated to some degree. For example, the Feast of the Annunciation almost always occurs within the Great Lent in the Orthodox calendar: in this case fish 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 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 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 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 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. 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:
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 mandated fasting and abstinence from meat on all Fridays of the year, a practice that was reemphasized by Phoebe Palmer and became standard in the Methodist churches of the holiness movement. 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"; John Wesley kept a more rigorous Friday Fast, fasting from sundown until sundown in accordance with the liturgical definition of a day. 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:
Good Friday, which is towards the end of the Lenten season, is traditionally an important day of communal fasting for Methodists. 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

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 Wednesdays 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 Apostolic Church 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. 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 is held at noon, and because no food can be consumed before communion, it is traditional for people to abstain from food until mass is over. 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 fasts that are ordained in the canon of the Church of Ethiopia are:
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 seven 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. This annual observance occurs exactly three 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

, the Protestant Reformer, held that fasting served to "kill and subdue the pride and lust of the flesh". As such, the Lutheran churches often emphasized voluntary fasting over collective fasting, though certain liturgical seasons and holy days were times for communal fasting and abstinence. Certain Lutheran communities advocate fasting during designated times such as Lent, especially on Ash Wednesday and Good Friday. A Handbook for the Discipline of Lent delineates the following Lutheran fasting guidelines:
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."

Reformed

, the figurehead of the Reformed tradition held that communal fasts "would help assuage the wrath of God, thus combating the ravages of plague, famine and war." In addition, individual fasting was beneficial in that "in preparing the individual privately for prayer, as well as promoting humility, the confession of guilt, gratitude for God's grace and, of course, discipling lust." As such, many of the churches in the Reformed tradition retained the Lenten fast in its entirety. The Reformed Church in America describes the first day of Lent, Ash Wednesday, as a day "focused on prayer, fasting, and repentance" and considers fasting a focus of the whole Lenten season, as demonstrated in the "Invitation to Observe a Lenten Discipline", found in the Reformed liturgy for the Ash Wednesday service, which is read by the presider:
Good Friday, which is towards the end of the Lenten season, is traditionally an important day of communal fasting for adherents of the Reformed faith. In addition, within the Puritan/Congregational tradition of Reformed Christianity, special days of humiliation and thanksgiving "in response to dire agricultural and meteororological conditions, ecclesiastsical, military, political, and social crises" are set apart for communal fasting.
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.

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. In addition to the normal fast and black fast, some undertake what is referred to as the Daniel Fast in which only one type of food 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.

The Church of Jesus Christ of Latter-day Saints

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 ; this is usually Sunday breakfast and lunch, thus the fasting occurs between the evening meal on Saturday and the evening meal on Sunday. 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. Church apostle Gordon B. Hinckley stated: "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 in 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. in 2004, in 2015.
Sunday worship meetings on Fast Sunday include opportunities for church members to publicly bear testimony of their belief in Jesus Christ and church doctrine 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:
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 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. 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
Yudhishthira asks Bhishma, "what constitutes the highest penances?" Bheeshma states "....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.
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. 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 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, 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 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 s 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 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 and similar may be delivered from sins.

Islam

In Islam, fasting requires abstinence from food, drink and sexual activity. However, there is also a broader sense of fasting which includes abstaining from any falsehood in speech and action, abstaining from any ignorant and indecent speech, and from arguing and fighting. 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. 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.

Ramadan

Fasting is obligatory for every Muslim one month in the year, during Ramadan. Each day, the fast begins at dawn and ends at sunset. During this time Muslims are asked to remember those who are less fortunate than themselves as well as bringing them closer to God. Non obligatory fasts are two days a week as well as the middle of the month, as recommended by the Prophet Muhammad.
Although fasting at Ramadan is fard, exceptions are made for persons in particular circumstances:
Muslims are encouraged to fast optionally outside of Ramadan as well, as a way of asking forgiveness from or showing gratitude to God and especially during the following days:
Outside of Ramadan and the above recommended dates, Muslims can fast anytime, except for the forbidden days. Styles of fasting mentioned in the sunnah include:
Fasting is forbidden on these days:
Prior to undertaking a Jain fast, a person must make a vow, or a formal statement of intent.

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.
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. 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. 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.
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. Fasting is only observed from sunrise to dusk, and there is more leniency 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:
There are other minor customary fast days, but these are not universally observed, and they include:
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

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.".
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."
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||"
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 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||"
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."
"Fasting on Ekadashi, adoration of Thakurs 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."

Taoism

The bigu fasting practice originated as a Daoist technique for becoming a xian, and later became a Traditional Chinese medicine cure for the sanshi. Chinese interpretations of avoiding gu "grains; cereals" have varied historically; meanings range from not eating particular foodstuffs such as food grain, Five Cereals, 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. A fast should also be maintained on the full moon day of each month. It is essential on the spiritual fasting day 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 is avoided, with water taken as needed.

Japanese history

Japan has used fasting as punishment for meat consumption. Consumption of domesticated animals was banned by Emperor Tenmu in 675 A.D. from April to September due to Buddhist influences; however, wild game was exempt. Nevertheless, these laws were regularly flouted. According to the Engishiki, in the Heian Period, fasts began to be used as punishment for the Buddhist sin of meat consumption, initially for 3 days. Eating meat other than seafood was seen by Buddhist elite as a kind of spiritually corrupted practice. By the Kamakura Period, much stricter enforcement and punishments began, with an order from Ise Shrine for a fast for 100 days for eating wild or domestic animals as defined above, while anyone who ate with someone who ate "meat" was required to fast for 21 days, and anyone who ate with someone who ate with someone who consumed "meat" was required to fast for 7 days.

In alternative medicine

Although practitioners of alternative medicine promote "cleansing the body" through fasting, the concept is quackery with no scientific basis for its rationale or efficacy.
During the early 20th century, fasting was promoted by alternative health writers such as Hereward Carrington, Edward H. Dewey, Bernarr Macfadden, Frank McCoy, Edward Earle Purinton, Upton Sinclair and Wallace Wattles. All of these writers were either involved in the natural hygiene or new thought movement. Arnold Ehret's pseudoscientific Mucusless Diet Healing System espoused fasting.
Linda Hazzard, a notable quack doctor, put her patients on such strict fasts that some of them died of starvation. She was responsible for the death of more than 40 patients under her care.
In 1911, Upton Sinclair authored The Fasting Cure, which made sensational claims of fasting curing practically all diseases, including cancer, syphilis, and tuberculosis. Sinclair has been described as "the most credulous of faddists" and his book is considered an example of quackery. In 1932, physician Morris Fishbein listed fasting as a fad diet and commented that "prolonged fasting is never necessary and invariably does harm".
There is no scientific evidence that prolonged fasting provides any significant health benefits. Negative health complications from long term fasting include arthritis, abdominal cramp and orthostatic hypotension.