The digestive tract is the part of the body most exposed to environmental threats, including bacteria, viruses, parasites, and toxins. It requires the most immune system support. When food is broken down in the intestines, it travels through the blood to the liver, the largest organ of the body's natural detoxification system. The liver breaks down and removes the toxic by-products produced by digestion, including natural ones and the chemicals now present in the food supply. During fasting, the liver and immune system are essentially freed to detoxify and heal other parts of the body.
God uses fasting as a teaching tool on one of the annual holy days He commands us to keep. In Leviticus 23:27 God says “afflict your souls” on the Day of Atonement. The New Unger’s Bible Dictionary points out that afflicting your souls is a reference to fasting. So on this particular holy day God commands that His people forgo both food and water for 24 hours as a means of humbling themselves before Him, seeking Him and His will and guidance in life.
Lowers insulin levels: Intermittent fasting acts on insulin in two ways. First, it boosts your adiponectin levels, which helps restore insulin sensitivity to prevent weight gain and diabetes. Second, fasting decreases your fasting insulin levels. Lowered insulin is the cue your body needs to make the switch to burning stored fat instead of glucose.
During the Biosphere 2 experience and the Calerie trial, some researchers hoped CR would become a viable regimen. But the enthusiasm has significantly cooled. While side effects were an issue, people’s inability to stick to a significantly reduced calorie load every day was the hammer blow. At this point, fasting was CR’s heir apparent: It seems eating nothing on occasion might be better than eating less all the time.
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".
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."
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.