The Muslim month of Ramadan is here and over a billion Muslims around the world will fast in this month. Muslims fast because there is an injunction in the Qur’an telling them to do so. The Qur’an reminds Muslims that many prophets and their followers before Muhammad (Peace be upon him) were also ordained fasting. The Jewish Passover and Christian Lent are also examples of fasting, although the nature and duration of their fasting may be different than Muslim fasting. The verse that ordains Muslims to fast ends with the sentence, “… and fasting is good for you only if you knew” (Q2:184). This article attempts to explore some recent findings on the changes that occurs in the human brain and their effects on human mind and behaviours during fasting. In today’s time and age, we normally eat three meals a day but never ask why. There is no biological rule requiring us to eat so frequently except that we have been conditioned to become hungry if we don’t eat for a few hours. The homo sapiens came to exist about 250,000 years ago but agriculture developed just over 10,000 years ago. This means that for about 240,000 years, humans did not eat three meals a day. They killed a gazelle or other animals, ate it with their clan over a couple of days, and then went hungry for the next few days. They did not die from not eating three times a day. However, the modern times are different as we have all the food we want, and we live in a culture of eating that has made our bodies lazy and turned off their abilities to run on their own energy sources. Overeating has led to many biological illnesses and medical research has confirmed clear advantages of fasting for the human body. Research is now starting to grow on the effects of fasting on human brain and overall mental health. It should be clear that by fasting we mean intermittent fast (IF) from dawn to dusk and a practice that ends after thirty days. The dietary objective in fasting is calorie restriction, otherwise the physical and psychological benefits will not manifest. 


Effects of fasting on the brain 
An average human brain has 100 billion cells and consumes 22% or more of our total body’s energy but the unique thing is that the brain becomes more active during food deprivation. Normally, the brain gets its energy from glucose (blood sugar) between meals by breaking down glycogen that is stored in the liver and muscles. As glycogen energy depletes from fasting, humans are endowed with a mechanism to create new bits of glucose through a process called gluconeogenesis that adversely affects the muscles. But when we fast, after about 3-4 days, the liver starts to convert our body fat to create chemicals called ketones. One of these ketones (beta-HBA) is a highly efficient fuel source for the brain, allowing it to function during extended hours of fasting and at the same time, decrease dependence on gluconeogenesis, providing relief to the muscles from which they are derived. This process of the brain also makes itself more cognitively alert than when it acts from the source of body glucose.
As fasting increases production of the protein called Brain Derived Neurotrophic Factor (BDNF), the brain also builds more neurons (brain cells) to help itself work efficiently. Studies show that building neurons delay the onset of decline in both motor skills and spatial memory and restore mental capacity. During fasting, the number of mitochondria in the nerve cells increase to enhance the ability of neurons to form and maintain connections, which result in improved learning and memory. An extremely interesting phenomena discovered during fasting is known as autophagy as the brain breaks down old and damaged cells and recycles them into new ones. Through this self-eating process, the toxins are removed from the brain delaying the development of neurodegenerative diseases like Alzheimer’s, Parkinson’s and Huntington’s. Most of these findings have been confirmed on lab animals because controlled studies on human brain is difficult. Experiments with rats have shown clear link of autophagy soon after food restriction and improved mental functioning in ageing animals. Behavioural Psychologists experimenting with lab rats have shown that fasting animals had better balance and learned skilled behaviour faster than those that were free to eat as much as they want. It has been observed also by the scientists that after a few days of fasting, the body adapts to starvation and starts to release high amounts of catecholamines including adrenalin, norepinephrine and dopamine into the brain. These hormones and neurotransmitters are produced as a result of fight or flight response preparing the body for exertion and they act as mood enhancers. For people with depression, doctors prescribe medication that augment these feel-good chemicals produced naturally through fasting. Some studies have shown improvement of depression and anxiety symptom scores in 80% of the patients just after a few days of fasting. This is because of the increased amount of endorphin release that begins after fasting. Studies have also demonstrated improved sleep patterns in patients with insomnia compared to pre-fasting levels and a possible decrease in migraine due to serotonin levels going up. Studies have shown also that children suffering from epileptic seizures had fewer incidences of seizures when placed on calorie restriction diet or IF as fasting may counteract the over-excited signals exhibited in epileptic brain. These findings are evident from studies done mostly in the last twenty years and published in some of the top international research journals. Having observed so many benefits of fasting on both body and brain, Mark Mattson, Chief of Neurosciences Lab at the National Institute of Aging and Professor of Neuroscience at John Hopkins University, wrote in his article, “Challenging Oneself Intermittently to Improve Health” in Dose Response (2014) that we should encourage “…society wide effort to re-introduce intermittent fasting… to save humanity from epidemic of diseases.” Likewise, many ongoing researches continue to show positive effects of fasting on the human brain. 


Effects of fasting on psychological well-being
Research in psychology has also demonstrated positive outcomes of fasting on cognition and memory. For all those who fast, patience is learned to withstand the temptation of food and other environmental stimuli and the ability to hold off which in turn, enhances the virtue of self-sacrifice, enabling a person to be humbled and attain maturity. Fasting becomes a training in self-control and self-regulation as a fasting person learns to regulate his or her daily routine in a prescribed manner thus teaching discipline. Fasting makes us realise our strengths and weaknesses and we learn to tame ourselves in ways that can lead to self-improvement. This learning of being able to do things that can otherwise be quite difficult for many people, develops confidence and a sense of self-efficacy. A fasting person may say to oneself, “If I can fast, I can do other difficult things in life.” Another psychological benefit for many people is an increase in a sense of belongingness with a group or community. During Ramadan, Muslim families and friends eat and share food with others, especially with the less fortunate. This practice of sharing and caring encourages altruistic qualities and a sense of gratitude for what one has that one can give to others or receive.
It is important to realise that when fasting starts, the brain is deprived of immediate glucose intake and may experience weakness, hunger and headaches for the first few days, but just in a few days, the brain eases up and the body finds a new set point making us feel less hungry. Not only our body and brain adapt to the new set point, we also feel comfortable with lower weight. With all these obvious benefits of fasting, medical researchers have introduced a 5:2 diet plan in which the participants eat regular meals five days a week and fast or follow strict diet regimen two days a week.


Effects of fasting on spirituality
Fasting is prescribed not only for the body and mind but also for elevating one’s level of spirituality as the person fasting is encouraged to expel from within oneself the impurities of thought and character. In a way, this practice releases oneself from earthly bonds and joins the person with the sacred. The time spent otherwise in eating and drinking can now be spent on reflecting about the purpose of being and making efforts toward attaining the ultimate goals in life leading to self-actualisation in this world and the hereafter. The metaphysical belief that the ego component of soul drags oneself to earthly desires while fasting restrains the ego and elevates the status of soul is held by followers of many faiths and consequently fasting is encouraged and practiced by people around the world. A word of caution is necessary for those advanced in age or suffering from medical conditions to seek advice from a physician before fasting.
Dr Haque is a Professor in Clinical Psychology at the School of Psychology and Social Work, Doha Institute for Graduate Studies.
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