Measuring God: the science of  Christain fasting


Fasting is practised in various religions. Examples include Lent in Christianity; Yom Kippur, Tisha B’av, Fast of Esther, Tzom Gedalia, the Seventeenth of Tamuz, and the Tenth of Tevet in Judaism. Muslims refrain from eating, drinking and sex during the entire daytime for one month, Ramadan, every year.

Fasting, diversity

Details of fasting practices differ. Eastern Orthodox Christians fast during specified fasting seasons of the year, which include not only the better-known Great Lent, but also fasts on every Wednesday and Friday (except on special holidays), together with extended fasting periods before Christmas (the Nativity Fast), after Easter (the Apostles Fast) and in early August (the Dormition Fast). Members of The Church of Jesus Christ of Latter-day Saints (Mormons) generally abstain from food and drink for two consecutive meals in a 24-hour period on the first Sunday of each month.

Like Muslims, they refrain from all drinking and eating (unless they are children or are physically unable to fast). Fasting is also a feature of ascetic traditions in religions such as Hinduism and Buddhism. Mahayana traditions which follow the Brahma’s Net Sutra may recommend that the laity fast “during the six days of fasting each month and the three months of fasting each year”. Members of the Baháʼí Faith observe a Nineteen Day Fast from sunrise to sunset during March each year”.

 Fasting, Motivation

Fasting has been applied for diverse reasons. For instance, the Wikipedia (2022) notes that 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. For political reasons, it is understood that, 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 (Garcia, 2007).

A retrospective study by Harinarayanan, (1986) opined that the political leader 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.

The BBC News (2019) also explained that 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.

Shaw, (2008) also asserts that César Chávez undertook a number of spiritual fasts, including a 25-day fast in 1968, promoting the principle of non-violence, and a fast of ‘thanksgiving and hope’ to prepare for pre-arranged civil disobedience by farm workers.

A similar study by Espinosa and Garcia (2008) also confirmed that Chávez regarded a spiritual fast as “a personal spiritual transformation”.  However, Shaw (2008) is of the view that other progressive campaigns have adopted the tactic.

For medical application, Norman(2003) holds the view that 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 (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(, 2010).

Despite its recent surge in popularity, fasting is a practice that dates back centuries and plays a central role in many cultures and religions.

What is Fasting?

Fasting is defined as the abstinence from all or some foods or drinks for a set period of time; there are many different ways of fasting. It is also a spiritual discipline that is taught in the Bible. Jesus expected His followers to fast, and He said that God rewards fasting. Fasting, according to the Bible, means to voluntarily reduce or eliminate your in-take of food for a specific time and purpose.

Fasting, Biblical Perspective

Jesus explained that fasting should be done without fanfare; and not “of a sad countenance” so as to “appear unto men to fast … But thou, when thou fastest, anoint thine head, and wash thy face; That thou appear not unto men to fast except your Father, who is with you even in private. He can see what is done in private, and he will reward you.…” (Matt. 6:16–18). This also means that, when one fast, there is a reward by God!  So another way to measure the existence of God is through fasting. In general, most types of fasts are performed over 24–72 hours.

When something needs to change, we fast to promote a reformation (Lewis, 2020). For instance, in Nehemiah 1:3-4, “And they said unto me, the remnant that are left of the captivity there in the province are in great affliction and reproach: the wall of Jerusalem also is broken down, and the gates thereof are burned with fire. And it came to pass, when I heard these words, that I sat down and wept, and mourned certain days, and fasted, and prayed before the God of heaven.”

When should we fast?

Let’s examine examples from God’s Word.

A case for discussion is cemented on Joel 1:14, “Sanctify ye a fast, call a solemn assembly, gather the elders and all the inhabitants of the land into the house of the Lord your God, and cry unto the Lord”. We find here that we are to call for a fast to declare our dedication or to show God we mean business – it’s a way of turning to the Lord. Joel 2:12, “Therefore also now, saith the Lord, turn ye even to me with all your heart, and with fasting, and with weeping, and with mourning:”

We can also fast when there impending judgement.  For instance, in Jonah 3:5, “So the people of Ninevah believed God, and proclaimed a fast, and put on sackcloth, from the greatest of them even to the least of them”.

King David also tried to release God’s mercy for his baby by fasting. Even though it was not to be, David knew the principle of fasting.

This was demonstrated in II Samuel 12:16, “David therefore besought God for the child; and David fasted, and went in, and lay all night upon the earth.” When we need direction and are determined to hear from God we should fast. But when everything is running smoothly, we should also fast as part of our ministry and service to God.

This was also demonstrated in Acts 13:2, “As they ministered to the Lord, and fasted, the Holy Ghost said, separate me Barnabas and Saul for the work whereunto I have called them.” It’s part of our service until the Bridegroom comes for us. Luke 2:37: “And she was a widow of about fourscore and four years, which departed not from the temple, but served God with fasting’s and prayers night and day.”

Fasting, the Science

Regulates blood sugar

From empirical literature, studies have found that fasting may improve blood sugar control, which could be especially useful for those at risk of diabetes (Link, 2018).

For instance, one small study involving 10 people by Arnason et al.(2017) with type 2 diabetes demonstrated  that short-term intermittent fasting significantly decreased blood sugar levels. Another article by Gunnars (2020) asserts that both intermittent fasting and alternate-day fasting were as effective as limiting calorie intake at reducing insulin resistance (Adda and Kubala, 2020).

A previous review by Gunnars (2019) is further of the view that decreasing insulin resistance can increase your body’s sensitivity to insulin, allowing it to transport glucose from your bloodstream to your cells more efficiently.

Coupled with the potential blood sugar-lowering effects of fasting, this could help keep your blood sugar steady, preventing spikes and crashes in your blood sugar levels. A retrospective study by Heilbronn et al. (2005) found that the impact of fasting on blood sugar may differ between men and women.  The study demonstrated that practicing alternate-day fasting impaired blood sugar control in women, but had no effect in men.

Fasting fights Inflammation

On the other hand, acute inflammation is a normal immune process used to help fight off infections while chronic inflammation can have serious consequences for your health. Hunter (2012) study demonstrates that inflammation may be involved in the development of chronic conditions, such as heart disease, cancer and rheumatoid arthritis.  In view of this, one review by Spritzler(2018) found that fasting can help decrease levels of inflammation and help promote better health.

Faris et al.(2012) study which involved 50 healthy adults found that intermittent fasting for one month significantly decreased levels of inflammatory markers  A similar small retrospective study by Aksungar et al.(2007) discovered the same effect when people fasted for 12 hours a day for one month.

The interesting thing is that one prospective animal study by  Choi et al.(2016) demonstrates that following a very low-calorie diet to mimic the effects of fasting reduced levels of inflammation and was beneficial in the treatment of multiple sclerosis – a chronic inflammatory condition.

Fasting supports Cardiovascular Health

Ghana is currently battling with heart disease (Bosu & Bosu, 2021) and more than one in four adults in Ghana have hypertension. This high prevalence has persisted for decades and is similar in rural and urban populations.  The authors further note that Ghana’s pooled prevalence of hypertension of 27% is similar to that of Nigeria (28.9%).

Another study by Atibila et al. (2021) found that hypertension in the urban settings was significantly higher compared to rural settings. Age structure and population type accounted for 65% of the observed heterogeneity in hypertension estimates.

What needs to be done is to advocate for lifestyle changes as they are the most effective ways to reduce risk of heart disease. Interestingly, studies have found that incorporating fasting into daily activities could improve our heart health.

One review by Kerri-Ann (2018)  found that eight weeks of alternate-day fasting reduced levels of ‘bad’ LDL cholesterol and blood triglycerides by 25% and 32% respectively(Link, 2021).

Another retrospective study by Beleslin et al.(2007)  in 110 obese adults found  that fasting for three weeks under medical supervision significantly decreased blood pressure, as well as levels of blood triglycerides, total cholesterol and ‘bad’ LDL cholesterol.

Another prospective study by Horne et al. (2008) involving 4,629 people linked fasting with a lower risk of coronary artery disease, as well as a significantly lower risk of diabetes, which is a major risk factor for heart disease.

Fasting support brain function and avert Neurodegenerative Disorders

Though studies are limited to animal research, several studies have found that fasting could have a powerful effect on brain health. For instance, Li et al.,(2013) study found that practising intermittent fasting for 11 months improved both brain function and brain structure. Other animal studies have reported that fasting could protect brain health and increase the generation of nerve cells to help enhance cognitive function (Lee et al, 2000; Tajes et al, 2010). Link (2018) explained that because fasting may also help relieve inflammation, it could also aid in preventing neurodegenerative disorders.

Two animals’ studies, (Dua and Mattson 1999; Halagappa et al.,2007) found that fasting may protect against and improve outcomes for conditions such as Alzheimer’s disease and Parkinson’s.  Nevertheless, more studies are needed to evaluate the effects of fasting on brain function in humans (Link, 2018).

Fasting supports weight loss and boosts metabolism

Gunnars(2020) review asserts that many dieters pick up fasting looking for a quick and easy way to lose weight. Link (2018) hold the view that abstaining from all or certain foods and beverages should decrease your overall calorie in-take, which could lead to increased weight loss over time. A previous study by Zauner et al,(2000)  also found that short-term fasting may boost metabolism by increasing levels of the neurotransmitter norepinephrine, which could enhance weight loss.  One review by Tinsley and Bounty (2015) demonstrated that whole-day fasting could reduce body weight by up to 9% and significantly decrease body fat over 12–24 weeks.

Another review by Varady (2011) also found that intermittent fasting over 3–12 weeks was as effective in inducing weight loss as continuous calorie restriction and decreased body weight and fat mass by up to 8% and 16% respectively . The same author further found that fasting is more effective than calorie restriction at increasing fat loss while simultaneously preserving muscle tissue.

Fasting increases growth hormone secretion

Human growth hormone (HGH) is a type of protein hormone that is central to many aspects of your health. Review by Mawer (2019) found that fasting could naturally increase HGH levels. One study by Salgin et al. (2012) in 11 healthy adults demonstrated that fasting for 24 hours significantly increased levels of HGH.  Another retrospective small study by Hartman et al. (1992) in nine men found that fasting for just two days led to a 5-fold increase in the HGH production rate.  A similar study by Lanzi et al. ( 1992) also found that fasting may help maintain steady blood sugar and insulin levels throughout the day, which may further optimise levels of HGH, as some research has found that sustaining increased levels of insulin may reduce HGH levels.

Fasting averts aging and promote longevity

One retrospective study by Goodrick et al. (1982) in rats that fasted every other day experienced a delayed rate of aging and lived 83% longer than rats that didn’t fast.  Three animals’ studies by ( Goodrick et al.1983; Honjoh et al,2009; Sogawa et al.2000) experienced  similar findings, reporting that fasting could be effective in increasing longevity and survival rates.

However, current research is still limited to animal studies. Further studies are needed to understand how fasting may impact longevity and aging in humans.

Fasting fights cancer and increases the effectiveness of chemotherapy

Animal and test-tube studies indicate that fasting may benefit the treatment and prevention of cancer. Rocha et al. ( 2002) involving a single rat study found that alternate-day fasting helped block tumor formation.  Another test-tube study by Lee et al (2012) found that exposing cancer cells to several cycles of fasting was as effective as chemotherapy in delaying tumor growth and increased the effectiveness of chemotherapy drugs on cancer formation. Unfortunately, most research is limited to the effects of fasting on cancer formation in animals and cells (Link, 2018) .

Side effect of Fasting

 Two studies, Marshall (2012; Moore and Jason, 2016) hold the view that in rare occurrences, fasting can lead to the potentially fatal refeeding syndrome upon reinstatement of food intake due to electrolyte imbalance.

The Wikipedia (2022) defines refeeding syndrome as a metabolic disturbance that occurs as a result of reinstitution of nutrition in people and animals who are starved, severely malnourished, or metabolically stressed because of severe illness. When too much food or liquid nutrition supplement is eaten during the initial four to seven days following a malnutrition event, the production of glycogen, fat and protein in cells may cause low serum (blood) concentrations of potassium, magnesium and phosphate.

Fasting in alternative practice

Fasting in alternative medicine practice should be done under a competent practitioner. A case study was highlighted by Harriett (2016) where one 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.  A retrospective work in 1932 by physician Morris Fishbein listed fasting as a fad diet and commented that: “Prolonged fasting is never necessary and invariably does harm”. Mostly, practitioners in alternative medicine profession employ this as a detoxification tool. Griffith, (2000) notes that the concept of fasting as a healing protocol in alternative medicine started in the early 20th century, promoted by alternative health writers such as Hereward Carrington, Edward H. Dewey, Bernarr Macfadden, Frank McCoy, Edward Earle Purinton, Upton Sinclair and Wallace Wattles.

Take Home

Studies have demonstrated the many impact of fasting from different perspective. Be it for religious or health concerns. Additionally, there are also negative aspects of relying on some specific intermittent fasting protocols. For instance, Daniel’s fast diet is not necessary as part of a healthy lifestyle. Instead, you may want to try applying healthy eating principles from the diet, such as eating foods that are high in fibre, plant-based and minimally processed.

Also, employing fasting as an alternative medicine treatment should be under some qualified practitioners as studies have also confirmed deaths from fasting done under unqualified alternative medicine practitioners.

Fasting have both spiritual and unspiritual benefits.  Science has demonstrated the health benefits and limitations of Biblical types of fasting such as Daniel’s fast.

Disclaimer- The information is meant for general interest only and should not be considered as medical advice.

The author is the President of the Nyarkotey College of Holistic Medicine & Technology (NUCHMT)/African Naturopathic Foundation. E-mail: [email protected]


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