In fiqh or Islamic law, fasting during the month of Ramadan is an obligation for Muslims as it is stated in Surah Al-Baqarah verse 183, which was revealed over 1400 years ago in the second year of Hijriah. Thus, for 14 centuries Muslims have carried out the obligation to fast in Ramadan. However, fasting as a culture is much older than Islam itself. Several highly civilized ancient nations, such as the Romans, Egyptians or Chinese, had the habit of fasting for various purposes, including as a form of cultural ritual or belief.

During the 20th century,  medical and health scientists conducted numerous studies that demonstrated the health benefits of fasting.  These medical studies contributed to the development of Evidence Based Medicine (EBM). EBM is research-based, using scientific method and the latest data for clinical practice or healthcare services. Thus, the latest knowledge, combined with clinical experience, is used as a basis for medical decisions.

Various medical studies have been conducted to examine the relationship between fasting and body health. One of the studies is a cohort study with data sources from services for pregnant women, childbirth, infants and toddlers conducted by 81 students of the University of Tehran of Medical Science. This research shows that fasting during Ramadan can lower glucose levels and body weight. This study evaluates body weight, body mass index (BMI), glucose, triglycerides (TG), cholesterol, lipoprotein, Low Density lipoprotein (LDL), high density lipoprotein (HDL), and Very Low Density lipoprotein (VLDL), before and after Ramadan. The results showed that fasting during Ramadan can lead to a decrease in glucose levels and body weight, thereby preventing potential diabetes and obesity.

Additionally, research has been collected to develop safe fasting guidelines for patients with chronic diseases, such as diabetes mellitus, chronic kidney failure, and coronary heart disease. These guidelines help guide patients with chronic illnesses on whether or not fasting is appropriate for their clinical condition. For example, patients with low or moderate health risks (such as patients with stable angina) may fast as long as they continue to undergo treatment and their clinical condition allows it. High-risk patients, such as those with severe heart failure, are advised not to fast.

There is also research that examines the use of energy to fuel metabolism. When fasting, the body will automatically save energy due to reduced physical activity. Energy consumption is reduced and the metabolic rate decreases. Even though there is no protein calorie intake, energy needs for metabolism can still be met during the fasting period because the body has a warning system that involves nerve and hormonal responses. This mechanism can detect a lack of calories with a span of 24 hours, and then responds to it as a form of compensation for the body through a process called catabolism.

The body will compensate for the lack of nutritional intake during fasting by reducing the effects of hunger. In the first 24 hours of fasting, blood glucose-fatty acid supplies and liver-muscle glycogen will be used as a source of energy for the body. However, the amount is insufficient compared to the need for daily metabolism when not fasting. If there is no more nutritional intake, triglycerides from fat tissue will be broken down into fatty acids and ketones, which are used by non-brain tissue as the body's energy source. The brain can only derive energy from pathways that produce glucose, using 5 grams of glucose/hour under normal conditions, while also utilizing ketones as an energy source when awake, sleeping, or when thinking.

According to neuroscientist Mark P Mattson from the School of Medicine at Johns Hopkins University, during normal conditions, the liver stores glucose for energy, particularly for the brain, before turning to stored body fat. It takes 10 to 12 hours to deplete calories in the liver before the body turns to fat stores as energy for metabolism. After eating, glucose will be used as energy, and the excess will be stored in the liver, while the fatty elements are stored in adipose tissue. But during fasting, once the glucose stores have been depleted, the body breaks down fat stores for energy, albeit at a slower metabolic rate.

People who are undergoing a weight loss program must go on a diet so that they are free from added calories for 16 hours. But Mattson suggests an easier way by stopping eating at 7 pm, then continuing by not having breakfast the next day, and eating again at 11 o'clock in the afternoon. This is what is called the 7 : 11 diet method, as written in The New England Journal of Medicine. In short, this pattern is formed by eating in limited times each day, by shortening the time span of eating to 8 hours per day.

What about pregnant and lactating women who are fasting? In fiqh, pregnant and lactating women are not required to fast during Ramadan as it may negatively affect their health and the well-being of their fetus or baby. Instead, they must compensate for missed fasts at other times.

Apart from matters related to Islamic law, there is also medical research on non-pregnant women, pregnant women, and breastfeeding mothers in West Africa, which has produced interesting results. According to the study, there were no significant differences in the levels of various substances in the blood such as glucose, free fatty acids, triglycerides, ketones, alanine, insulin, glucagon, and thyroxine among these three groups of respondents. This indicates that fasting during Ramadan does not have a significant impact on pregnant and lactating women.

Other research has also shown that fasting can promote a balance between anabolism and catabolism, allowing amino acids and other substances to support the process of cell rejuvenation throughout the day by producing blood glucose and supplying amino acids. During fasting, amino acids are oxidized slowly and ketones do not increase in the blood, thereby avoiding an acidic condition in the blood.

Fasting during Ramadan also does not affect the function of the thyroid gland. The study showed that fasting did not affect plasma levels of thyroxine, free thyroxine, triiodothyronine, and thyroid-stimulating hormone in male respondents. Fasting during Ramadan also does not affect the hormone progesterone, but it may reduce the hormone prolactin in 80% of research respondents. This finding provides hope for women with infertility issues caused by high levels of prolactin. Additionally, Ramadan fasting may increase HDL and alpha-1 apoprotein levels and lower LDL, which is beneficial for heart and blood vessel health.

Evidence-Based Medicine and Bucailleism

The multitude of medical studies revealing the positive correlation between fasting during Ramadan, as written in the Quran, and health has sparked interest in further research. This has led to an exploration of whether other verses in the Quran can also be explained through modern science.

The benefits of fasting for health that have been proven by modern science have formed the basis of evidence-based medicine. For Muslims, this will certainly further strengthen their faith. The examination of the compatibility of the Quran's verses with science extends beyond health topics and has been pursued by many scholars.

One of the scholars is Maurice Bucaille, a French gastroenterology surgeon and author of several books on the relationship between scriptures and modern science. In 1973, Bucaille was appointed as the family physician to King Faisal of Saudi Arabia. Bucaille has produced many books and other writings on the relationship between the scriptures and modern science. His well-known work is "La Bible, le Coran et la Science" (The Bible, The Quran, and Science), published in 1976. The Indonesian edition was published under the title "Bible, Quran dan Sains Modern", followed by other books, including another "Qur'an and Modern Science", and another book translated into Indonesian, "Asal Usul Manusia Menurut Bibel, Alquran dan Sains". Bucaille also wrote another book, "Les Momies des Pharaons et la Médecine", or "Mummies of the Pharaohs: Modern Medical Investigations" which investigates the truth of the story of the Pharaoh who drowned in the Red Sea while pursuing Moses, by means of medical investigations on the mummy.

Later, Buccaile's research has attracted many followers and has led to the emergence of Bucailleism, a belief that many verses in the Quran can be explained using modern scientific principles.

This academic and religious search can be considered a form of ijtihad, which then made him convert to Islam. According to fiqh, if the ijtihad is correct and benefits the people, then they will get two rewards. Meanwhile, if the ijtihad is wrong, either in part or in whole, then they will get only one reward. This is because academic disagreements are common, and newer findings may replace previous ones, leading to further synthesis and antithesis. Similarly, Bucaille's research has elicited responses from other scientists who disagree with his findings.

For example, Daniel Golden believes that Bucailleism, which examines the verses of the Quran on various topics, follows the theory of Christian creationism, which sees every birth or emergence of living things in nature as a divine intervention. However, the difference between the two is that while creationism rejects modern science, Bucailleism embraces it. (Daniel Golden, "Strange Bedfellows: Western Scholars Play Key Role in Touting 'Science' of the Qur'an", Wall Street Journal, 23/1/22). Literary critic Sameer Rahim, on the other hand, regards Bucaille's claims as a joke by other scientists and theologians (Sameer Rahim "Pathfinders: The Golden Age of Arabic Science by Jim al-Khalili: review",The Telegraph, 8/10/ 2010).

Despite this, we will not delve into the debate over Bucaille's theory which examines the verses of the Quran on various topics. In accordance with the initial theme, instead, we focus on the health benefits of fasting, which modern medical research has proven.

By observing the fasting of Ramadan and fulfilling the religious obligations as written in Surah Al-Baqarah verse 183, Muslims can reap the health benefits of this holy month. Let us all complete this blessed Ramadan fasting with gratitude for these blessings.

Djoko Santoso
Professor, Faculty of Medicine, Universitas Airlangga
Chairman of Health Department, Indonesian Council of Ulama, East Java