While according to some, fasting is said to be good for health, for fitness and for promoting weight loss, others opine just the opposite. In general, fasting is understood to be an abstaining from food (as water as well in some cases) for a period of time ranging from hours to days.
Many religions put a ritualistic emphasis on fasting and there is the understanding that fasting can not only help the body but can also help a person make certain spiritual gains. 
Fasting has been common among most populations of the world from ancient times. According to many modern experts as well, fasting is good for a number of different reasons:
Fasting helps rest the system: Our intake everyday causes our digestive system undergo the process of digestion several times each day.
Fasting for a period is thought to offer some rest and respite for the body’s systems. This is also thought to provide time for the system to heal and rejuvenate itself.
Cleansing and elimination of toxins: Fasting is thought to cleanse the body of toxins and help flush them out. This is particularly true in the case of water fasting, so that the system is flushed and cleansed of toxins and other harmful substances.
Even the mind can get help achieve greater clarity with fasting, it is claimed. According to some experts, fasting helps improve the health of the liver since it detoxifies the liver.
Helping one remain younger: For a long time now, it has been thought that the renewing and refreshing impact of fasting can help slow the aging process. This is probably because of the fact that fasting reduces glucose and insulin in the blood and therefore reduces oxidative stress on the body.
Good for the immune system: Since the intestines are also rested during a fast, this can help to increase the amount of good bacteria that lines the intestines helping to give a boost to the immune system.
Fasting can also increase white blood cell count according to some studies and this can help to destroy harmful bacteria in the body.
Good for weight loss: When you deprive your body of food it is natural to assume that the body will turn to fat stores for energy and start to break that down for use. This, according to some experts is the case and fasting can help you lose weight.
