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Can fasting help shape your brain?

Simran D’Mello St. Xavier’s College (Autonomous), Mumbai, Maharashtra, India.

"I fast for greater physical and mental efficiency." - Plato

It is a common misconception among people that fasting is a ‘modern trend’. In reality, it is a practice that has been followed by our ancestors for the longest time in observance of holy traditions or to simply keep healthy. There has been a drastic change in the way we think, look and go about living our lives in this modern world. There were no extravagant terms used for such practices at that time as they were simply considered as a way of living. ‘Intermittent fasting’ has gained extreme popularity among the masses, especially during this pandemic when we are constantly trying to keep fit and healthy, physically as well as mentally. ‘We already know that fasting can help us get our body in shape but does it help get our brain in shape too? Hmmm.. let’s see.

What is intermittent fasting?

It is a practice wherein we do not consume food for a certain period of time in order to increase the level of ketones in our body. When we are not fasting, our body cells use glucose as a primary fuel. Fasting uses up the glucose stored in the liver. This causes the fat cells to release fats. These fats move to the liver where they get converted to ketones - which is used as a source of energy instead of glucose. The conversion of glucose to ketones is termed a ‘metabolic switch’. This switch takes place after a span of 10-14 hours of fasting depending on an individual’s metabolism.

There are different types of intermittent fasting:

  • 16:8 method: Fasting takes place for 16 hours and we eat during the remaining 8 hours.

  • 5:2 method (Fast diet): Twice in a week we take in 500-600 calories while we eat our normal diet for the rest of the five days.

  • Eat-Stop-Eat: Once or twice a week, we do not eat for 24 hours.

  • Alternate day fasting: As the name suggests, we fast on alternate days.

  • The Warrior Diet: By following this, you fast all day and feast at night. We can eat during the 4 hours window.

  • Spontaneous meal skipping: There is no strict plan to be followed. We can skip meals as and when we feel we are not hungry.

What does fasting do to your brain?

Intermittent fasting is proved to be extremely beneficial for maintaining brain health. It slows down the process of ageing. It stimulates the production of nerve cells in the hippocampus region which thereby activates the metabolic switch of glucose to ketones during the fasting period.

Beta-hydroxybutyrate is the ketone that stimulates the transcription of a molecule called BDNF (brain-derived neurotrophic factor). This BDNF makes the neurons stronger in those parts of the brain which control the memory and helps to increase the neuroplasticity of the brain. Neuroplasticity basically tells us how the human brain adjusts, grasps new skills, stores memories and information and recoups after a disturbing brain injury.

The level of leptin hormone decreases while that of adiponectin and ghrelin increases during fasting. This helps to maintain neural pathways. Ghrelin is the hormone that activates the synaptic plasticity in the hippocampus region.

It also helps to start the process of ‘autophagy’ during which the body itself consumes food, thus knocking down its cells and reusing its own destroyed cells and proteins so as to build healthy bones. Autophagy helps to prevent Alzheimer’s disease and Parkinson’s. It protects the brain from getting damaged as a result of strokes and helps in reducing seizures. Studies indicate that when you are fasting, the brain uses fewer carbohydrates. This as a result reduces the number of epileptic seizure attacks.

Survey-based on the effect of intermittent fasting on the brain

A recent survey was carried out across people of different ages. The majority of the respondents were between 20-30 years of age.

Many claimed to have tried it out and seen results be it mentally in terms of brain health or physically in terms of being fit and losing weight. However, there were some who had read about it before but never practised it to date. One respondent stated that “It would be beneficial if done in a controlled manner. However, getting obsessed with it would lead to physical and mental issues.”

Some felt it would work better on youngsters and depends on person to person. It does not necessarily work the same for all. Others believed that “In a world where food distribution is so unnatural it has become a necessity for the upper-middle and rich class.” The majority of the respondents mentioned that they have fasted before. When asked for the reason behind doing it, most said for religious purposes, to keep healthy and to achieve fitness goals. Some also cited Type II Diabetes as a reason for practising intermittent fasting.

Most of the respondents felt that intermittent fasting has a positive impact on the brain as it helps us gain self-control. One respondent stated that “There's a specific balance that you have to maintain so that your brain gets a steady and sufficient amount of glucose. If the fasting routine is followed with expert's opinions then yes it is healthy however it is not advisable to do it irregularly.”

There were a few who believed that it would personally have a negative impact on their brain.

A respondent said that “I think food is something that not only gives us energy but also helps in the betterment of our mood and the overall productivity. Starving ourselves just for the sake of weight loss would hinder our mental growth, making us tired and angry for no reason.”

Another respondent claimed that “Intermittent or short term may not be very harmful, but if it's for prolonged periods, then it's harmful because it will deplete the brain of glucose & minerals necessary to carry out cognitive activities.”


There are a variety of benefits ( beyond just losing weight), mentally and physically that one can enjoy through fasting provided it is done in the right way under the guidance of experts. It instils in us a sense of accomplishment even though it might be difficult to adapt to and follow initially. We can divert our focus from counting calories to consuming foods that nourish not only our body but also our soul, guilt-free. By doing intermittent fasting, we lower our risks of contracting diseases and improve the brain’s overall health. Intermittent fasting helps us to strike a balance between eating foods that give us happiness and foods that keep us healthy which is of vital importance to maintain brain health.


Phillips, M. C. L. (2019, October 17). Fasting as a therapy in neurological disease.

Wnuk, A. (n.d.). How Does Fasting Affect the Brain?

Nadir, M. (2021, April 8). The Complete Guide To Fasting | Intermittent Fasting. SQUATWOLF.

D. (2021, January 4). This Is How Intermittent Fasting Improves Your Brain. The Best Brain Possible.

Effects of fasting during Ramadan on seizure control and quality of life in patients with epilepsy. (2020, November 1).

Kim, G. J. O. (2017, December 20). The amazing changes intermittent fasting does to your body and brain.

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