Fasting has its advantages from the point of view of health and hygiene. Islam wants a Muslim to be healthy, clean, alert, agile and energetic. "Fast to be healthy," had said the Holy Prophet Muhammad (S.A.W.). And physicians today acknowledge the many benefits of fasting that ensure health and the soundness of one's body and mind. Some of these positive points have a direct influence on psychology and physique of the fasting individual.
Fasting has been found to be an effective treatment for psychological and emotional disorders. It helps a person to firm up his will, cultivate and refine his taste and manners, strengthen his conviction of doing good, avoid controversy, petulance and rashness, which all contribute towards a sane and healthy personality. Besides nurturing resistance and ability to face hardships and endurance, fasting reflects on outward physical appearance by cutting out gluttony and getting rid of excess fat. The benefits of fasting on health do not stop there but are instrumental in alleviating a number of physical diseases, including those of the digestive systems, such as chronic stomachache, inflammation of the colon, liver diseases, indigestion, and conditions such as obesity, arteriosclerosis, high blood pressure, asthma, diphtheria and many other maladies.
A Swiss physician Dr. Barsilus noted that: The advantages of hunger as a remedy exceed those ingesting medicine several times.
As readers are well aware, several physicians advise patients to skip meals, sometimes for a few days, before prescribing them a controlled diet.
Generally speaking, fasting hastens the destruction of the decaying tissues of the body by means of hunger, and then builds new tissues through nutrition. This is why some scientists suggest that fasting should be regarded as an effective means of restoring youthfulness and longevity. However, Islam exempts from fasting sick and old people whose health is bound to deter.
But fasting should have its regulations too, and not simply the in orderly skipping meals, that is bound to harm health and stamina, rather than improving them. Here again Islam provides the answer, and in order to realize the benefits of fasting, it recommends the late midnight meals called Sahar (before the formal start of a fast) and the breaking of the fast at the time prescribed. Of course, to ensure good health one should abstain from gluttony after breaking fast.
Moderation: It is difficult to identify the moderation in the desires for food and sex because of the different needs and energies of individuals. Moderation of an individual may be considered as exaggeration or shortage for another. The relative moderation is to have only the quantity that is sufficient, away from greed and fill. The best criterion in this regard is that which was stated by Imam Ali ibn Abi Talib (AS):
"Son! May I instruct you four words after which you will no longer need medicine? Do not eat unless you are hungry. Stop eating while you are still hungry. Chew food deliberately. Before sleeping, go to toilet. You will not need medicine if you follow."
In the holy Quran, there is a Verse gathering the whole matter of medicine. It is: "...Eat and drink but do not be excessive." (7:31)