The Neuroscience of Fasting

As a neuroscientist, I’m always trying to understand how our brain deals most effectively with the daily issues we encounter.  

So once the end of February rolls around and my fellow Baha’is and I start to prepare for the Fast, it’s always helpful for me to understand some of the possible underlying reasons behind fasting. Baha’is fast every year for primarily spiritual reasons, but the Baha’i teachings also say that “innumerable effects and benefits are concealed therein:”

Even though outwardly the Fast is difficult and toilsome, yet inwardly it is bounty and tranquillity …. Verily, I say, fasting is the supreme remedy and the most great healing …. All praise be to the one true God Who hath assisted His loved ones to observe the Fast and hath aided them to fulfill that which hath been decreed in the Book.

There are various stages and stations for the Fast and innumerable effects and benefits are concealed therein. Well is it with those who have attained unto them. – Baha’u’llah, The Importance of Obligatory Prayer and Fasting, pp. xvi-xix.

Aside from the spiritual component, science has begun to find some very interesting pieces of biological information as to why fasting may ultimately help us on our path towards living a truly healthy, spiritual life. So if you’d like to join the global Baha’i community in its annual Fast, keep in mind some of the tangible benefits that voluntary fasting during the daylight hours may provide for your brain.

Fasting forces your brain to adapt and ultimately become more efficient. Our brain evolved over the course of millions of years, and for the vast majority of that time we lived from moment to moment. We didn’t have access to fast food or even regular meals, and not finding food would mean certain death.  Our brain knew this, so it evolved to focus intently when we approached starvation mode, because this was the time when we needed to have our wits about us to find food.  

In neuroscience, we see this occurring as a sort of “switch” that gets flipped in our brains when we’ve gone about 16 hrs. without any calories. That switch still exists in our brain, and research suggests that it still functions as it did thousands of years ago. This means that once your brain realizes that you haven’t had any food for about 16 hours (possibly 12 hours in women) it activates that switch to make you more focused, more alert and mentally on top of your game.

The brain is a remarkably adaptable machine, and activation of this fasting “switch” may increase natural chemicals in your brain that help make it a more efficient machine. Research indicates that intermittent fasting in this way can increase these natural chemicals (known as growth factors) which help act like your brains’ personal housekeeper, cleaning up debris and recycling anything needed for future activity.  

When you consider that your brain has about 85 billion neurons with thousands of connections to each of those, it’s easy to see why this housekeeping is critical. Research studies point to this housekeeping component as a way to prevent Alzheimer’s, Parkinson’s, age-related memory loss and even cancer, so it’s obviously important to keep a clean brain! An added benefit of increasing these natural growth factors in the brain is that they seem to act as natural antidepressants. In fact, we think that many of the antidepressant drugs on the market these days work by artificially increasing these brain growth factors.  

Finally, there are some very interesting findings in the field of neuroscience around training your willpower. We all have a network in our brain that has the job of acting as a “brake” on our emotions and the distractions in our lives. This is fairly unique to humans. That mental brake is why you can resist the temptation to eat that delicious piece of chocolate ganache cake sitting on a stranger’s plate next to you as you wait for your meal at a restaurant, whereas a dog would simply pounce on the plate to satisfy his hunger. This brake however, allows us to do some other very uniquely human things like empathize with others, even if we don’t agree with them, or show kindness to a total stranger.  

Contemporary neuroscience research suggests that we can strengthen this internal brake by activating it regularly, just like a muscle that you would train in the gym. The willpower necessary to inhibit your basic desire to eat and drink during the daylight hours for 19 days (in combination with the willpower to clear your mind for regular prayer), serves to slowly develop that brake. It may ultimately allow you to become more focused, more empathetic and to regulate your emotions more efficiently.

If you think about fasting from this perspective, then it really provides a means towards creating the best environment in our brain for modeling true Baha’i behaviors—love for others, kindness, empathy and a true sense of spiritual kinship with all humanity. Isn’t that something that our society needs now more than ever?