Ramadan starts again. What does a month of fasting do to your body?
On Sunday, Ramadan starts again, a month during which Muslims traditionally do not eat, drink, or have sexual intercourse. How does fasting affect your body? “We overeat very easily, as it’s a biological urge.”
On Sunday, March 10th, Ramadan begins at sundown for many Muslims, during which they fast between sunrise and sunset. It is a time of reflection, prayer, self-discipline, and dwelling on those who are worse off, but also a time of fellowship. After sunset, family and friends gather for dinner.
This year, Ramadan falls in spring. That means no eating or drinking—no, not even water—between about 7:15 in the morning and 6:30 at night. What does 11 hours without food or liquid do to your body? Internist-endocrinologist Maarten Soeters, who received his doctorate on fasting at the UvA, has the answer.
Tell me, what happens if we don’t eat anything for a day?
“Not much. We humans are well adapted to not eating. Our energy metabolism is very neatly and economically tuned, so we can get by for a while. Only when you don’t eat for a longer period of time, say after 14 or 18 hours, does something change. Then your body starts burning fat because that is a nice and easy source of energy. And we have a lot of that, a whole store of fat that contains energy for weeks or months. We know that people can go without food for a very long time, unfortunately partly because of the examples from the concentration camps in World War II.”
“Your body wants to avoid having to use protein because it consists of essential building blocks, and if they are broken down, you soon don’t do well. Then your muscle mass decreases, for example, and it’s harder to wake up.”
So basically fasting is very good for you?
“Well, there is quite a lot of hype about fasting and nutrition. In any case, there’s no harm in letting your body alternate between burning carbohydrates (which happens when you’ve just eaten) and fat (when you don’t eat for a while). Your body stays healthy if it has to adapt all the time, which has the difficult name of ‘metabolic flexibility.’ It is indeed healthy.”
What about fluids?
“You shouldn’t not drink for two weeks. Your body needs a certain amount of fluid every 24 hours. Otherwise, you dehydrate. But if you are healthy, you can do without water for a while. An average person can go without drinking for 10 hours if they catch up afterward.”
We here in the Netherlands follow the Gregorian calendar, which is based on the time it takes the Earth to rotate exactly one time around the sun. Our planet takes 365.25 days to do that, which is why we have a leap year once every four years.
The Islamic calendar follows the moon. A new month begins with a new moon. The Islamic year has 12 lunar months of alternating 29 and 30 days, a total of 354 days. Ramadan is the ninth month in this count, which therefore begins on a different day each year because of this count. In 2030, for example, Ramadan will fall around Boxing Day. Incidentally, for many Muslims, Ramadan also always ends on a different day: only at the moment when the first crescent of the new moon is seen over Mecca.
How do you make sure there are no deficiencies in certain nutrients?
“That doesn’t happen very quickly. In Western countries, we traditionally have three meals a day. But you can eat at other times just as well. If you look at evolution, tens of thousands of years ago our species couldn’t eat all day long either, purely because it wasn’t always available.
We know from the literature that gatherers sometimes didn’t eat anything for days and that when they came into a fertile environment, they stuffed themselves.”
“One of the reasons we currently have an obesity epidemic is precisely because our bodies are used to using energy sparingly. But in an environment of electric bikes, fast food that you can put directly into your mouth practically without chewing, and supermarket food that is high in calories, you overeat easily. Two thousand calories of supermarket food is different from two thousand calories of unprocessed vegetables. You can eat much more of the latter. Plus, we have a biological urge to eat a lot because our bodies have been trained to take into account the fact that there could be a famine tomorrow and we will be short on food. That’s how people become overweight.”
Do people now eat less on average during Ramadan? Or more, because compensation is made during the hours when you are allowed to eat?
“After sunset, people often ‘overeat’ during Ramadan. So, the health gains I describe above are then dwarfed because high-calorie, sweet things are eaten in the evening.”
Have our bodies perhaps become too accustomed to abundance?
“Absolutely. We see nothing but trouble from that in hospitals. People are overweight and overfed. An estimated 70 percent of healthcare costs are explained by lifestyle-related diseases, such as smoking, alcohol, and obesity. That just doesn’t seem to sink in with businesses and policymakers. Everyone currently fears they will have a hypoglycemic attack if they don’t eat on time. But fasting is not only common in the Islamic world, it used to be very common in both the Catholic and Protestant churches, too. We have simply forgotten in the Western world today that we are very good at not eating for a while.”
