The Health Benefits of Fasting

On the first day of Andrew’s neurology rotation, his attending turned to him and asked, “Name one thing that has been scientifically shown to prolong life.” Andrew, a newly minted 3rd year medical student, replied in his naivete, “Antibiotics, of course.” The attending shook his head no.  “Ok, vaccines?” he tried a second time.  Another head shake no.  “Um…surgery?”  No again. The attending finally replied that the answer was, in fact, decreased caloric intake.

Fasting is an age old tradition of many faiths and cultures, particularly within the Abrahamic faiths. Greek Orthodox Christians fast for a total of 180-200 days each year (the main fasting periods are the 40 Nativity Fast days prior to Christmas, the 48 days of Lent prior to Easter, and 15 days in August). Many of these fasts traditionally can be described as a variant of vegetarianism. Jews fast 6 days out of the year, with Yom Kippur being the most important of those days.  During these days, fasting – which includes abstaining from food and water — begins at sunrise and ends at sunrise the following day.  Muslims fast from sunrise to sunset for 28-30 days during the month of Ramadan, and the fasts are similar to the Jewish tradition in abstaining from both food and drink.

The number of studies during the past two decades looking at religiously motivated fasts has grown in number. Most of these studies have looked at three types of fasts: caloric restriction
(CR), alternate-day fasting (ADF), and dietary restriction (DR).

CR is defined as a reduction in total caloric intake by a certain percentage, usually 20-40%, of your total daily consumption. The average American consumes over 2800 calories a day despite the US Department of Agriculture recommendations that the average man and woman should eat 2400 and 1800 calories, respectively, per day to maintain weight.

Medical studies investigating CR have shown that it increased longevity in dogs, fruit flies, rodents, nematodes, spiders, primates, and zebrafish. Speaking in the strictest scientific sense, it is not known if the same is true in humans, as long term studies have not been conducted to date. It is thought that the anti-aging effect of decreased caloric intake is due to reduced energy use resulting in less production of reactive oxygen species and less oxidative damage. Simply put, it is thought that eating less results in less long term destruction of our body’s cells.

We recall one non-Muslim professor in medical school who fasted the “sawm of Dawud” or “fast of David” as it is commonly known as.  He did not refer to it as such, but he would fast every other day, believing that fasting was the only scientifically proven method to increase his lifespan. Alternate day fasting (ADF) studies have looked at alternating 24 hours periods of “feast periods” where the eater may consume food ad lib, and “fast periods” where only water is allowed.

Both CR and animal ADF studies have been to shown to extend their subjects’ lifespan. Both types of studies have also shown the retardation or prevention of many diseases including the top two killers in the United States: heart disease (namely atherosclerosis or plaque buildup) and cancer.

The third most commonly studied fast is dietary restriction, defined as a reduction in one or more component of a macronutrient (aka carbohydrates, proteins, or fats), but no reduction in total caloric intake. Research in animals suggests that reduction in carbohydrate or lipid intake does not have an effect on lifespan. Studies looking at protein, however, suggest a different story. A reduction in protein may increase lifespan by about 20%. These findings have also been noted in animal studies and further human studies are needed to make the same claim.  Yet the implications are potentially interesting for those who consume protein shakes and protein bars.

How does all this information relate to the religious fast of Ramadan? Does caloric intake decrease in Ramadan? Is one month even long enough to see an effect on health?

Clearly, fasting during Ramadan can provide a significant health benefit.  However, the healthy effect is limited by the many cultural practices that can sometimes be associated with Ramadan.  Studies show that Muslims sometimes consume a greater amount of sugary foods and drink during Ramadan, which would increase the number of empty calories ingested. This would counteract the health benefits of fasting as mentioned above.  Studies also show that certain cultures, especially those of the Arab Gulf region, consume more during Ramadan. It is customary for those cultures to significantly increase their nocturnal caloric intake, a large portion of which is animal protein. Other studies show that certain cultures, such as Indian Muslims, consume less during Ramadan. But the month long tradition is unlikely to confer a lasting benefit if people revert to pre-fasting dietary habits.

The practical message that Ramadan can give us is reflected in the prophetic hadith, “No human ever filled a vessel worse than the stomach. Sufficient for any son of Adam are some morsels to keep his back straight. But if it must be, then one third for his food, one third for his drink, and one third for his breath.”

So how we can reap the maximum health benefits from this blessed month? Two simple recommendations:

1. Do not neglect hydration with water. In a survival situation your body can potentially live up to three to five days without water and a lot longer without food (up to 3-4 weeks). The point is that replacing water with sugary drinks, energy beverages, teas, and coffee can contribute to dehydration, headache, mood swings and elevated blood pressure, amongst other adverse outcomes. Ensure that you and your family prioritize water intake more than the intake of other beverages.

2. Nix the empty calories! Stay away as much as possible from processed foods, eg. anything that comes prepackaged in a bag or box. Most of these foods satisfy a temporary craving and leave you wanting more. We call them “superficial foods” because they do not even penetrate the surface when trying to meet our daily nutritional needs.

Use Ramadan to form good eating habits among other things. Ramadan is a time of refocusing and reflection, a time to detach the self from worldly things and allow the soul to re-attach to its natural state of belief — to the oneness of God. Let us also strive to reflect that in the way we eat. If we can allow Ramadan to help us adhere to these principles, we would surely reap the health benefits of this blessed month.

Disclaimer: Prior to making any major dietary changes , especially for readers with chronic medical conditions, we recommend that you consult your personal physician.


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