Japanese Scientist Shows how Body is Cleansed during Fasting. Wins Nobel Prize
The 2016 Nobel Prize for ‘Physiology or Medicine’ was awarded to Japanese scientist Dr. Yoshinori Ohsumi for his discoveries of the underlying mechanisms of a physiological process called autophagy. 
Autophagy is a natural process by which the body degrades and recycles damaged cells, proteins and toxins. Autophagy comes from two Greek words, auto meaning “self” and phagy meaning “to eat.”
This is the body’s way of cleaning house. It happens during fasting and calorie restriction. If the body fails to engage in autophagy, damaged cells and structures can accumulate dangerously. Autophagy is one method that the body uses to naturally neutralize cancer cells and degrade cells infected by harmful bacteria and viruses.
Dr. Ohsumi was able to identify the genes that regulate autophagy and has linked disturbances of autophagy to a host of degenerative diseases.
Studies have actually shown that cells live longer and mitochondria make more energy in times of fasting or calorie restriction, compared to when eating regularly. 
Other studies suggest that regular fasting or calorie restriction (without starvation) can naturally hack the aging process in numerous ways. Calorie restriction has been shown to boost levels of nitric oxide, a Nobel prize-winning molecule that delivers essential rejuvenation and detoxification to the body. Calorie restriction has been shown to boost antioxidant and detoxification activity by activating Nrf2 pathways, and also have anti-inflammation effects.
Back in 1935, the first paper on calorie restriction was published. It suggested that lifespans could be extended and diseases could be avoided by restricting calories without hunger or starvation. 
In the most comprehensive study on calorie restriction to date, which spanned 20 years, the results were nothing short of amazing. The study divided Rhesus monkeys up into two groups. One group ate naturally, without restraint, and the other group ate a diet that was 30% less in calories.
After 20 years, 30% of the unrestricted diet group had died, and only 13% of the calorie-restricted group had died from age-related illness. This translates into an almost three-fold reduction risk in age-related diseases.
The monkeys that were calorie restricted had half the incidence of heart disease as the controls. Not one monkey in the calorie-restricted group acquired diabetes, while 40% of the monkeys that ate as much as they wanted became diabetic or pre-diabetic.
In one study, where a group of humans reduced their caloric intake by only 20% for 2-6 years, blood pressure, blood sugar, cholesterol, and weight were all significantly improved.
Looking at all the research, it is hard to find any other intervention that has such compelling benefits on health and longevity than eating just 20-30% less food.
Fasting of Prophet Muhammad (pbuh)
The Prophet, peace be upon him, would fast, not continuously, but periodically, throughout the year. It was his practice to fast and to encourage people to fast on specific days. These include:
1. Mondays and Thursdays
Aishah, the Prophet’s wife, narrated: “The Prophet was keen to fast on Mondays and Thursdays” [Tirmidhi 745, Nasai 2361, and Ibn Majah 1739].
2. Six days in the month of Shawwal
Shawwal immediately follows the month of Ramadan in the lunar calendar and offers a great opportunity to continue the good habits gained in Ramadan. It can be difficult to switch eating habits so quickly after Ramadan, so many find it fruitful to fast intermittent days after the end of Ramadan, and take advantage of the blessings.
Abu Ayyoob reported that the Messenger of Allah, peace and blessings be upon him, said: “Whoever fasts Ramadan and follows it with six days of Shawal, it will be as if he fasted for a lifetime” [Sahih Muslim].
3. 4. The White Days (Ayam Al-Beedh)
Abdullah ibn Amr ibn al-Aas said: The Messenger of Allah, peace be upon him, said to me: “It is sufficient for you to fast three days every month, because for every good deed you will have (the reward of) ten like it, so that will be like fasting for a lifetime” [Bukhari and Muslim].
The white days refer to the 13th, 14th, and 15th of the lunar calendar, so it may not be the same days each month of the solar Gregorian calendar. The days are named as such due to the moon being full and the light it reflects is at maximum. It’s not necessary to fast all three days.
5. Day of Ashura - 10th of Muharram
The 10th of Muharram, the first month of the Islamic calendar, commemorates the day Allah saved Prophet Musa, peace be upon him, and his followers pharaoh’s army. There’s no day better to fast in after Ramadan than Ashura.
Ibn Abbas was asked about observing of fast on the day of Ashura, whereupon he said: “I do not know Allah’s Messenger, peace be upon him, singling out any day’s fast and considering it more excellent than another, except this day (the day of Ashura) and this month, meaning the month of Ramadan” [Muslim].
6. Arafah - 9th of Dhul-Hijjah
For those not performing Hajj, fasting the first nine days of Dhul-Hijjah (the 10th being Eid Al-Adha) is recommended. In particular, the Day of Arafah, being the 9th of Dhul-Hijjah, is highly recommended.
Abu Qatadah reported: The Messenger of Allah, peace be upon him, was asked about the observance of fasting on the day of Arafah. He said, “It is an expiation for the sins of the preceding year and the current year” [Muslim].
The month of Shaban precedes the month of Ramadan, and is an ample opportunity to prepare for Ramadan, both spiritually and physically.
It was narrated that Aishah reported that the Prophet liked the month of Shaban more than any other month as far as supplementary fasting is concerned [Bukkhari].
Other Health Benefits of Intermittent Fasting
In addition to the findings of Dr. Yoshinori Ohsumi, other research studies  have found that intermittent fasting can deliver numerous health benefits, including:
1. Decreased diabetes risk
2. Decreased cardiovascular risk
3. Improved longevity
4. Protection against cancer
5. Reduced risk of neurological concerns
6. Decreased inflammation
7. Balanced lipid levels
8. Reduced blood pressure
9. Reduced oxidative stress
10. Balanced weight