Why is fasting beneficial?
Fasting has been an age-old tradition among various ethnic groups. With today’s fast-paced life and sedentary lifestyle, more and more people find themselves turning to food at odd hours of the day and, in essence, are being addicted to the pleasure signals created by watching high fat food images on television and are also consuming munchies that are freely accessible via food delivery agencies. This raises the question that we are all struggling to answer about the effects of more food than needed—we have diverged from our hunter gatherer roots and have been forced into a state of excess that has wreaked havoc on our metabolic framework. Let us elaborate as follows:
Types of fasting:
Fasting—meaning refraining from or a strong limitation of food apart from water for a prolonged period of time—includes intermittent fasting, periodic fasting, and long-term fasting.
These modes of food abstinence have metabolic effects that have helped in improving health and life span.
One of the main metabolic switches that happen with fasting is the glucose to ketone switch in energy metabolism.
Facts:
Prolonged periods of fasting result in a glucose to ketone switch in our metabolic processes—this has a beneficial effect in preserving cognitive function.
Caloric restriction refers to a restriction to 15-40% of normal nutrition without malnutrition.
Intermittent fasting ranges from 16 to 48 hours, and long-term fasting can range between 2-21 days.
When fasting has lasted at least 12 to 16 hours, there is a drop in glucose levels and a simultaneous drop in insulin levels as well; this causes free fatty acids to be generated from the lipids in adipocytes that are in turn metabolized by the liver to produce ketones that are used as an energy source.
The ketones are not only used as fuels, but they also participate in signaling pathways that can up-regulate the expression of beneficial factors that promote health.
For example, prolonged fasting up-regulates brain-derived neurotrophic factor (BDNF)—this factor can help with neural functioning and health.
When ketones are used as an energy source, this leads to a decrease in the respiratory exchange ratio, which is beneficial to weight loss secondary to greater metabolic energy efficiency.
Fasting and the resultant ketones in the system may also cause the body to express more antioxidants and cytoprotective enzymes that help in the prevention and progression of chronic disease processes.
The glucose to ketone switch may also decrease protein synthesis and increase autophagy, or the recycling of endogenous protein stores—this may help in the retention of lean body mass; this is not seen in caloric restriction alone.
Ketosis leads to a compensated metabolic status that helps with hunger cessation.
Fasting also causes a decrease in Leptin and insulin-like growth factors and an increase in adiponectin, which have long-term beneficial effects on health.
It is important to note that insulin-like growth factors can be documented in the pathogenic process of various cancers, therefore, a decrease in levels is beneficial to overall health.
The fasting state is conducive to decreased waist circumference and therefore improved cardiovascular health, improved antioxidant defenses in our body, enhanced cancer protective mechanisms, optimization of metabolic health, DNA repair and recycling of nutrients within our body, and overall well-being.
Note: Fasting is not for everyone. The person who is fasting must have normal secretions of glucagon, cortisol, growth hormone, and adrenaline to help maintain glucose and energy levels during the fasting state, therefore, practice caution and always discuss with health care professionals prior to embarking on a fasting schedule.
As shown above, this ancient practice of fasting has several positive effects. As always, I wish that you stay focused on your health and nutrition and live long and strong!
