Fasting is a willing abstinence or reduction from some or all food, drink, or both, for a period of time. An absolute fast (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. Also, extended fasting has been recommended as therapy for various conditions by health professionals of many cultures, throughout history, from ancient to modern.
Fasting is also a part of many religious observances.
What Is Fasting?
by Tom Clark
The Bible talks about the spiritual tool of fasting, which can be used properly or improperly. What is fasting, and how does God want us to fast?
Fasting, by definition, is going without food and/or drink for a period of time. Typically it is done for religious reasons and involves a person refraining from both food and drink (Esther 4:16), although there are variations that may be done for health reasons (a juice fast, for example, where one would refrain from eating and only drink juice for a period of time).
Fasting in the Bible
The practice of fasting is mentioned numerous times in the Bible as a reaction to various circumstances. Fasting was an act of repentance, as when the king of Nineveh ordered a fast after the preaching of Jonah (Jonah 3:5-9). Fasting was also a reaction to intense grief, as when the bones of Saul and his sons were buried (1 Samuel 31:13). We also find people fasting when God’s deliverance was needed, as when Jehoshaphat was approached by a large invading army (2 Chronicles 20:3).
The Bible also gives instructions about the attitude and approach we should have in fasting. Jesus warned about hypocritical fasting, trying to show off or make others feel sorry for us.In the New Testament, Anna, the prophetess, is described as serving God day and night with fasting and prayers (Luke 2:37). We read that John the Baptist taught his disciples to fast and Jesus Christ said His disciples would fast after His death (Mark 2:18-20). Paul and Barnabas prayed and fasted when they ordained elders in the Church (Acts 14:23). And Jesus Christ fasted 40 days and nights before facing Satan in an epic battle of spiritual will (Matthew 4:2).
Instructions about fasting
The Bible also gives instructions about the attitude and approach we should have in fasting. Jesus warned about hypocritical fasting, trying to show off or make others feel sorry for us (Matthew 6:16-17). Instead we should not “appear to men to be fasting, but to your Father who is in the secret place” (verse 18).Isaiah also contrasts selfish fasting with godly fasting marked by care and concern for others (Isaiah 58:3-10).
What is fasting and why do we fast? We see from the biblical examples that fasting should be used as a means to humble ourselves before God and seek His forgiveness, comfort, help, guidance, strength and His will. Fasting allows us to draw closer to God.
Fasting and the Day of Atonement
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.
What is fasting as taught by the Bible?
We can conclude that by command of God and by scriptural example, fasting is a tool that a Christian may use to seek a closer relationship with his or her Creator and petition God for help, guidance and a humble heart that is yielded to His will.
While fasting is an excellent tool for spiritual growth, those with diabetes or similar serious health conditions would be wise to seek professional advice before attempting to fast.
Fasting is related to prayer, Bible study and meditation, so you might find it helpful to read our related articles on these subjects.
What does it mean to fast?
What is the Biblical definition of fasting? It means to not ingest or take in ANY food or ANY water for a particular period of time. We find this definition in the book of Esther, where the Queen asks her uncle Mordecai to request others fast for her.
. . . fast for me, and do not eat nor drink three days, night or day. My maidservants and I will also fast in the same way. (Esther 4:16)
Biblical fasting is carried out for at least a day or more. As is hinted at in the Esther quote above, a complete day is considered from sunset of one day to sunset the next day.
What Is Fasting and Do I Need to Fast?
When your healthcare provider orders certain tests, you may be told to fast for several hours before the test or overnight. Here’s what you need to know to comply with your doctor’s instructions.
What Is Fasting?
Fasting is when you consume no food or drinks, with the exception of water, for a set period of time. It’s important to drink plenty of water, not just because you’re not eating, but because it’s easier to draw blood from your veins when you’re well hydrated.
Why Fasting Is Necessary?
The nutrients in the food and beverages you consume are absorbed into your blood stream and could impact factors measured by certain tests. Tests to determine your lipid levels (cholesterol, triglycerides and HDL) usually require fasting. You also will be told to fast before glucose testing. Other tests may also require fasting. If you don’t fast, or fast for a shorter time than prescribed, your tests could give inaccurate results, meaning you’ll likely have to repeat the test. If you think fasting is going to be a problem for you, please discuss it with your healthcare provider.
How Long Must I Fast?
Generally, before a lipid or a glucose tolerance test, you’ll be told to fast for eight hours. However, your healthcare provider may advise you differently. Always follow his/her instructions to the letter.
Continue to Take Medications
Be sure to take your usual medications unless told otherwise by your healthcare provider. If you’re taking vitamin/mineral supplements, ask whether you should continue to take those as well.
Breaking Your Fast
As soon as you’ve had your blood drawn, you’ll probably want to eat and drink something. It’s a good idea to bring along a snack so you can do so as soon as possible. Schedule your blood test for the early morning to minimize the length of time you’ll have to go without food.