How fasting during Ramadan rewires the body

When the last morsel of sahur is swallowed and the dawn call to prayer begins, something shifts inside the body of every Muslim observing the Ramadan fast. The change is as biochemical as it is spiritual.

Deprived of food and water until sunset, the body begins hunting for fuel in places it normally ignores.

Prof Sabo Ahmed Mohammed of the College of Health Sciences at the University of Jos in Nigeria has scientifically studied what happens next. "The body switches over to the stored form of energy: lipids," he tells TRT Afrika. "Lipid means fat and oil."

Every year during Ramadan, adult Muslims abstain from food, drink and sexual intercourse between dawn and sunset, devoting more time to worship and charity.

The practice may be primarily about a reaffirmation of faith, but the biological chain reaction it sets off — from fat-burning and cellular clean-up to sharper brain function — is now well understood by science.

What medical experts warn about is the indulgence at iftar that apparently undoes most of the gains.

Cellular clean-up

The human body runs on glucose, drawn from the food we eat. When that supply is cut off for an extended period, the body pivots to its reserves, burning stored fat for energy in a process known as ketosis.

For a fasting person, this can mean shedding excess fat that might otherwise lead to obesity — basically by relieving the knees and ankles of the burden of carrying too much weight.

But ketosis is only the beginning. Sabo says the body also uses the fasting window to target entirely something else: cancerous cells.

"The body has a way of mopping up cells that are becoming malignant or cancerous," he explains. "What is becoming a dysfunctional unit will now be mopped up and destroyed or utilised as an energy source."

The process is called autophagy – literally, self-eating – and it amounts to a built-in cancer prevention mechanism. Damaged or dysfunctional cells that might otherwise proliferate are identified, broken down and either expelled or converted into fuel.

The brain gets an upgrade too. When the body shifts from carbohydrate to ketone bodies like acetone and acetoacetate for energy, the brain actually prefers this fuel.

"The synapses in the brain will work better with some of the debris or dysfunctional accumulates being removed through the process of fasting," Sabo tells TRT Afrika.

The result, he says, is better clarity for anyone who fasts for a reasonable period.

Undoing the gains

None of this matters much if the person spends the hours between iftar (tradition of breaking one's fast after sunset) and sahur (pre-dawn meal before fasting starts) eating two or three times their normal intake. This is something many do.

"If you consider the amount of food some people eat between iftar and sahur, it's enormous, probably two or three times what they usually eat before Ramadan," says Sabo.

Just as overeating is counterproductive, so is experimenting with different foods each day of the fast.

Sabo warns that irregular meals confuse the digestive system. "No matter how much you eat, if it is erratic and irregular, you may end up confusing the gut, where digestive juice could be poured into the intestines. If food is absent in the stomach at the time, it could attack the intestines."

This, he says, is what causes the peptic ulcers so many people complain about. The culprit is irregularity in meals, not deprivation.

The alimentary system is smart enough to learn a person's eating schedule and adapt to it. Sabo advises those who fast to keep the schedule regular to ensure it cooperates during the monthlong Ramadan rituals.

Sabo also encourages physical activity during fasting hours, with the caveat that excessive heat exposure should be avoided to prevent dehydration. Movement, he says, helps the body function well and accelerate its internal clearance processes.

His final advice is to avoid food that is too spicy or sour, as either can irritate the digestive system and undo the benefits the fast is meant to bring.