Fasting is a longstanding part of many religious traditions, including the Jewish and Muslim observances of Yom Kippur and Ramadan. As you read this, billions of Muslims around the world are engaging in this declaration of faith that involves abstaining from food and drink from dawn until dusk. While fasting for Ramadan is down to spiritual beliefs, many of us choose to fast with the belief that it benefits our health. But what happen to our body when we fast?
A person’s primary source of energy is sugar called glucose, which usually comes from carbohydrates, including grains, dairy products, fruits, certain vegetables, beans and even sweets.
The liver and muscles store the glucose and release it into the bloodstream whenever the body needs it. However, during fasting, this process changes. After about 8 hours of fasting, the liver will use the last of its glucose reserves. At this point, the body enters a state called glucogenesis, marking the body’s transition into fasting mode.
Studies have shown that glucogenesis increase the number of calories the body burns. With no carbohydrates coming in, the calories in the body burns. With no carbohydrate coming in, the body creates its own glucose using mainly fat.
Eventually, the body runs out of these energy sources as well. Fasting mode then becomes the more serious starvation mode. At this point, a person’s metabolism slows down, and their body begins burning muscle tissue for energy. Although it is a well-known term in dieting culture, true starvation mode only occurs after several consecutive days or even weeks without food. So, for those breaking their fasting after 24 hours, it is generally safe to go without eating for a day unless other health conditions are present. (1)
“A detoxification process also occurs, because any toxins stored in the body’s fat are dissolved and removed from the body,” he adds, noting that after a few days of fasting, higher levels of endorphins – “feel-good hormones” are produced in the blood, which can have a positive impact on mental well-being. As mentioned previously, the study by Dr.Longo and colleagues suggests prolonged fasting may also be effective for regenerating immune cells. “When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged,” Dr.Longo explains. In their study, publish in the journal Cell Stem Cell, the team found that repeated cycles of 2 – 4 days without food over a 6-month period destroyed the old and damaged immune cells in mice and generate new ones.
Moreover, the team found that cancer patient who fasted for 3 days prior to chemotherapy were protected against immune system damage that can be caused by the treatment, which they attribute to immune cell regeneration. “The good news is that the body got rid of the parts of the system that might be damaged or old, the inefficient parts, during the fasting,” says Dr. Longo. “Now, if you start with a system heavily damaged by chemotherapy or aging, fasting cycles can generate, literally, a new immune system.”(2)
On the other hand, according to the UK’s National Health Service (NHS), there are numerous health risks associated with intermittent fasting.
People who fast commonly experience dehydration, largely because their body is not getting any fluid from food. As such, it is recommended that during Ramadan, Muslims consume plenty of water prior to fasting periods. Other individuals following fasting diets should ensure they are properly hydrated during fasting periods.
Fasting can also cause heartburn; lack of food leads to a reduction in stomach acid, which digests food and destroys bacteria. But smelling food or even thinking about it during fasting periods can trigger the brain into telling the stomach to produce more acid, leading to heartburn.(2)
Finally, to sum up, moderation is the key. Know the precaution step to avoid the potential risk. A person must understand his or her current health condition before proceeding to any sort of diet plan.