Upavas or fasting along with yoga and meditation have central position in the Hindu way of life. This helps in rejuvenation and fight against diseases by strengthening immunity. This Indian knowledge system has received respect from the West when scientific
research coined the term ‘intermittent fasting’ for which the Japanese cell biologist Yoshinori Ohsumi won the Nobel Prize in Medicine in 2016.
Ohsumi’s work elucidated the method by which cells recycle and renew their content though a process called autophagy. His main finding was that during fasting, autophagy is activated, which helps in slowing down the aging process, has a positive impact on cell renewal, improves body immunity, and even helps in weight loss.
Most of the religions in the world follow fasting of different styles. For example, Muslims and Christians follow fasting for one month during one year. However, in Hinduism, there are different types of fasting in a week, such as fasting on Mondays by women, fasting on Thursdays, Saturdays, on full moon days, etc, as prayer to particular gods, in which regular meals are taken only once a day except a few
snacks during the day time, and avoiding food at night. The duration of fasting varies from 12 to 20 hours, depending on the days’ importance.
Ohsumi termed the observance of fasting as intermittent fasting. He discovered that degraded parts of the cells are recycled and the cell contents renewed through a process called autophagy.
Hindus have been observing fasting, or upavas, from time immemorial as a sacred religious practice, formulated by insights of spiritual leaders and rishis of India. Such practices have attained respect during modern times in the West, under the new term of intermittent fasting, which has found place in the dictionary of health science.
Delineating Yoshinori Ohsumi’s Work
The 2016 Nobel laureate discovered mechanisms underlying autophagy, a fundamental process for degrading and recycling cellular components. Autophagy denotes ‘self-eating’. This concept emerged during the 1960s, when researchers first observed that the cell could destroy its own contents by enclosing it in membranes, forming sack like vesicles that are transported to a recycling compartment, called the lysosome, for degradation. Difficulties in studying the phenomenon were removed through a series of brilliant experiments in the early 1990s by Yoshinori Ohsumi that led to a new paradigm in our understanding of how the cell recycles its content. His discoveries opened the path to understanding the fundamental importance of autophagy in many physiological processes, such as in the adaptation to starvation or response to infection. Mutations in autophagy genes can cause disease, and the autophagic process is involved in several conditions including cancer and neurological disease.
Degradation: A central function in all living cells
In the mid-1950s, scientists observed a new specialised cellular compartment containing enzymes that digest proteins, carbohydrates and lipids. This specialised compartment is referred to as ‘lysosome’ and functions as a workstation for degradation of cellular constituents. The Belgian scientist Christian de Duve was awarded the Nobel Prize
in Physiology or Medicine in 1974 for the discovery of the lysosome. New observations during the 1960s showed that large amounts of cellular content, and even whole organelles could sometimes be found inside lysosomes. The cell therefore appeared to have a strategy for
delivering large cargo to the lysosome. Further biochemical and microscopic analysis revealed a new type of vesicle transporting cellular cargo to the lysosome for degradation. Christian De Duve coined the term autophagy to describe this process. The new vesicles were named autophagosomes.
During the 1970s and 1980s, researchers focused on elucidating another system used to degrade proteins, namely the ‘proteasome’. Aaron Ciechanover, Avram Hershko and Irwin Rose were awarded the 2004 Nobel Prize in Chemistry for “the discovery of ubiquitin-
mediated protein degradation”. The proteasome efficiently degrades proteins one-by-one, but this mechanism did not explain how the cell got rid of larger protein complexes and worn-out organelles. Could the process of autophagy be the answer and, if so, what were the mechanisms?
A groundbreaking experiment
Yoshinori Ohsumi had been active in various research areas, but upon starting his own lab in 1988, he identified the first genes essential for autophagy. The results showed that autophagy is controlled by a cascade of proteins and protein complexes, each regulating a
distinct stage of autophagosome initiation and formation This was a major breakthrough and Ohsumi published the results in 1992. Carbohydrates are broken down into individual glucose (sugar) units, which can be linked into long chains to form glycogen, which is then stored in the liver or muscle. However, there is very limited storage space for glycogen in the body.
When we run out of space to store glycogen, the liver starts to turn excess glucose into fat. Some of this newly created fat is stored in the liver, but most of it is exported to other fat deposits in the body and there is almost no limit to the amount of fat that can be created.
Glycogen is the most easily accessible energy source. It is broken down into glucose molecules to provide energy for the body’s cells. Glycogen can provide enough energy to power much of the body’s needs for 24-36 hours. After this, the body will primarily break down fat for energy.
An equation for weight loss
Fat plus inhaled oxygen give out exhaled carbon dioxide, water and energy. About 84% fat is changed to CO2 and 16% fat is excreted as H2O. Diet and exercise serve as major contributors to fat loss. A nutritious diet that provides a proper calorie deficit combined with sufficient exercise is the recipe for sustainable fat loss. Now, let us see different stages of intermittent fasting:
1. By 12 hours, body starts to break down and burn fat.
2. By 18 hours, body switches to fat-burning mode and is generating significant ketones. Under normal conditions, the concentration of ketones in the plasma ranges between 0.05 and 0.1 mM. When we fast or restrict carbohydrates in the diet, this concentration can reach to
5-7 mM. As their level in the bloodstream rises, ketones can act as signalling molecules, similar to hormones, to tell the body to ramp up stress-busting pathways that reduce inflammation and repair damaged DNA for example.
3. Within 24 hours, cells are increasingly recycling old components and breaking down misfolded proteins linked to Alzheimer’s and other diseases This process is called autophagy.
4. By 48 hours, without calories or with very few calories, carbs or protein, the growth hormone level is up to five times as high as when one started fasting
5. By 54 hours, insulin has dropped to its lowest level point since fasting started and body is becoming increasingly insulin-sensitive, which is especially good if one has a high risk of developing diabetes, and provides protection from chronic diseases of aging including cancer.
6. By 72 hours, the body is breaking down old immune cells and generating new ones. Prolonged fasting for 72 hours has been shown to preserve healthy white blood cell or lymphocyte counts in patients undergoing chemotherapy.
Type 2 diabetes is fundamentally a disease of too much sugar in the body. When we eat glucose, insulin stores the excess in our cells. Over time, if all our cells and storage systems become overloaded, the remaining glucose spills over into the blood. The body requires a certain amount of energy every day to survive. The heart, brain, kidneys, liver, etc. all require energy even if one is lying in bed. Fasting allows the body to burn off its excess sugar.
Meditation and yoga
Spiritual leaders in India have prescribed meditation and yoga from time immemorial which have reappeared in modern times through a series of experiments in the laboratory. Exercising in the gymnasium meets the target partially since it does not induce peace and calm for inner body, which can only be brought about by meditation and yoga. There are different prescriptions designed by spiritual leaders of modern India like Sudarshan Kriya developed by Sri Sri Ravishankar, Kriya by Sri M, meditation process by Sad Guru and so on. To build healthy, modern India in both body and spirit, it is worthwhile to contemplate on any of the streams prescribed by our spiritual leaders.
*The writer is Emeritus Professor, Cochin University of Science and Technology, Kochi
