Yoshinori Ohsumi is a Japanese Biologist that was recently awarded the Nobel Prize for advancing the knowledge of cellular autophagy. Intermittent fasting, or IF for short, is an eating regimen in which one cycles between periods of feeding and extended periods of fasting. I know what you’re wondering, what is autophagy and what does IF have to do with it? Well, intermittent fasting is the process that initiates cellular autophagy. (More on autophagy in a moment) Thanks to the work of Dr. Ohsumi, we now have even further evidence of the benefits of this misunderstood, therapeutic weight loss strategy.
Intermittent fasting has a history as old as mankind itself. Yet, the mere mention of it in most social circles now-a-days will likely illicit confused stares and perhaps even accusations of having an eating disorder. Numerous studies have shown that implementing an intermittent fasting regimen can have powerful therapeutic benefits. Unfortunately most people are so entrenched in the dogma of 3-6 meals per day (due to an addiction to sugar and refined carbohydrates) that the thought of skipping more than one meal (on purpose) is simply an unfathomable concept. The foods included in the standard american diet illicit hormonal reactions that truly do make fasting a difficult acquisition. There are quite a few time consuming steps that one should take prior to attempting to implement a successful fasting regimen, but that’s a topic for another day. (Learn more)
Though the credible advocates of intermittent fasting are far too numerous to mention, one doctor in particular has been on the forefront of advancing awareness of its many benefits.
With the publication of two best-selling books on the topic in 2016, Dr. Jason Fung of Ontario Canada provides an excellent road map to success in both The Obesity Code and the how-to manual that he co-wrote with Jimmy Moore entitled The Complete Guide To Fasting. Both have become essential reading to maximizing the benefits of intermittent fasting.
I know what you might be thinking, this doesn’t prove anything in regards to the safety and effectiveness of intermittent fasting at all. After all, anyone can write a book, or win a Nobel Prize (…oh, wait). Still need more evidence to stave off the naysayers? Well, how bout some solid science. Don’t mind if I do …
Here are several evidence-based health benefits of intermittent fasting, complete with linked references to scientific studies and literature:
When you refrain from eating for an extended amount of time, several important things happen. Your body initiates a cellular reparative process that alters hormone levels that make stored body fat more accessible.
Some of the changes that occur in your body during fasting are as follows:
* Blood levels of insulin drop significantly, which facilitates the burning of fat for fuel (1).
* The body induces an important cellular repair process that removes waste material from your cells (6).
Many of those who utilize intermittent fasting are doing so for the purpose of weight loss (9).
In theory, when fasting intermittently, you are eating fewer meals. Provided you don’t compensate by overeating, you are taking in less calories on average over the course of time. Most importantly though, intermittent fasting enhances your hormone function to facilitate this weight loss. Lower insulin levels, higher growth hormone levels and increased amounts of nor-epinephrine all increase the breakdown of body fat and facilitate its use for energy. For this reason, short term fasting actually increases your metabolic rate by as much as 14%, helping you burn even more body fat (10, 11). Interesting that this is diametrically opposed to the current day conventional wisdom that somehow eating more frequently speeds up metabolism. That is simply a myth that has no basis in science.
If you are one to put credence in the oversimplified calories in vs. calories out theory (CICO), I guess it could be said that intermittent fasting works on both sides of that equation. It boosts your metabolic rate (increasing calories out) and reduces the amount of food you eat (reducing calories in).
Here’s a video clip interview with Dr. Jason Fung explaining weight loss and muscle retention as it pertains to intermittent fasting:
According to a 2014 review of the scientific literature, intermittent fasting can result in weight loss of 3-8% over 3-24 weeks (12). This is a significant amount. These same participants also decreased their waist circumference by 4-7%, which indicates that they lost visceral belly fat, the harmful fat located in the abdominal cavity known to cause disease. One review study also showed that intermittent fasting resulted in less muscle loss than continuous calorie restriction (13). So many myths, so little time.
Type 2 diabetes has become so common in recent decades that it’s not an exaggeration to refer to it as an epidemic. This debilitating metabolic disorder results from the combination of high blood sugar levels in the context of insulin resistance. Improving insulin sensitivity will result in the lowering and controlling of blood glucose levels. In human studies on intermittent fasting, fasting blood sugar has been reduced by 3-6%, while fasting insulin has been reduced by 20-31% (12). One study conducted on diabetic rats revealed that intermittent fasting provided protective properties against kidney damage, one of the most severe complications of diabetes (13).
Intermittent fasting, in concert with a well formulated low-carbohydrate diet have been known not only to improve insulin sensitivity, but in many cases to reverse, or stave off the progression of type 2 diabetes (12).
Oxidative stress and inflammation are two of the main contributing factors to the progression of aging and many chronic metabolic diseases (14). It involves unstable molecules called free radicals, which cause adverse reactions with other important molecules (like protein and DNA) and cause damage to them (15). Several studies show that intermittent fasting may enhance the body’s resistance to oxidative stress (16, 17). Additionally, studies show that intermittent fasting can help fight inflammation, and other key drivers of common diseases (17, 18, 19).
Heart disease is currently the world’s #1 killer (20). Intermittent fasting has been shown to improve numerous different risk factors, including high blood pressure, total and LDL cholesterol, blood triglycerides, inflammatory markers and blood glucose levels (12, 21, 22, 23). As discussed earlier, intermittent fasting can improve upon biomarkers of oxidative stress, inflammation, and hyperinsulinemia, all of which are considered common measures of cardiac health risk.
When we fast, the cells in our body initiate a cellular “waste removal” process called autophagy (7, 24). “Autophagy is a normal physiological process in the body that deals with destruction of cells in the body. It maintains homeostasis or normal functioning by protein degradation and turnover of the destroyed cell organelles for new cell formation.” Intermittent fasting facilitates and accelerates this process. This video provides a brief overview of autophagy (please excuse the robot voiceover, as this clip has been translated from Japanese)
The autophagial pathway involves the cells breaking down and metabolizing broken and dysfunctional proteins that build up inside cells over time. Increased autophagy may provide protection against several diseases, including cancer and Alzheimer’s disease (25, 26). You’ve likely heard the buzz words detox or cleanse thrown around in non-scientific circles in the context of juicing and the like. Well, autophagy as it pertains to intermittent fasting is the only TRUE cleansing and detoxification process. Think of it as a detox on the cellular level.
We all know cancers are often characterized by an uncontrolled growth of cells. Many cancer cells are glucose dependent. Fasting has been shown to have several beneficial effects on metabolism that can lead to a reduced risk of cancer. Fasting starves glucose dependent cancer cells. It only makes sense that cancer cells that thrive on glucose for growth would be deminished when their fuel is taken away.
Here’s a short talk by Mark Mattson, one of the foremost experts on neurology from Johns Hopkins University
Although more human studies are currently underway, promising evidence from animal studies indicates that intermittent fasting may help prevent cancer (27, 28, 29, 30). There is also some evidence on human cancer patients, showing that fasting reduced various side effects of chemotherapy (31).
What is good for the body is good for the brain as well. We’ve already discussed the positive effects that intermittent fasting can have in regards to improvements in insulin sensitivity in the body. It only makes sense that IF would decease insulin resistance for the brain as well. Reducing oxidative stress, inflammation and lowering blood glucose levels have positive affects on cognition and brain function. Several studies in rats have shown that intermittent fasting may increase the growth of new nerve cells, which have enormous benefits for brain function (32, 33). It also increases levels of a brain hormone called brain-derived neurotrophic factor (BDNF) (32, 34, 35), a deficiency of which has been implicated in depression and various other brain abnormalities (36). Animal studies have also shown that intermittent fasting protects against brain damage due to strokes (37).
Alzheimer’s disease is the world’s most common neurodegenerative disease. There is currently no cure available for Alzheimer’s patients , so prevention is of the utmost importance. A study in rats shows that intermittent fasting may delay the onset of Alzheimer’s disease or reduce its severity (38). In a series of case reports, a lifestyle intervention that included daily short-term fasts was able to significantly improve Alzheimer’s symptoms in 9 out of 10 patients (39). Animal studies also suggest that fasting may protect against other neurodegenerative diseases, including Parkinson’s and Huntington’s disease (40, 41).
One of the most interesting applications of intermittent fasting may be its ability to extend lifespan by slowing the aging process. Studies in rats have shown that intermittent fasting extends lifespan in a similar way to that of continuous calorie restriction (42, 43). In some of these studies, the effects were quite dramatic. In one, rats that fasted every other day lived 83% longer than rats who weren’t fasted (44). Although this is far from being proven in humans, intermittent fasting has become enormously popular amongst the anti-aging crowd, as I’m sure you can imagine. Given the known benefits for metabolism and health markers, it only makes sense that intermittent fasting could help you live a longer and healthier life.
As discussed earlier, fasting can be a much easier and a nearly effortless acquisition when conducted in a state fat adaption. To learn more about how this process staves off hunger and optimizes the burning of stored fat, visit this link (click here). The fasting process is optimized once you’ve adapted your body to seeking its fuel from fat instead of carbohydrates. Though you will still eventually achieve a state of ketosis while fasting, being previously fat adapted simplifies and quickens the process, and allows for much less struggle in regards to hunger pangs. This graph, provided by the Quantified Body Podcast, illustrates the increase in serum ketone levels during the fasting state.
Should you decide to look further into intermittent fasting as a possible aid in weight loss or the reversal of metabolic disease, might I suggest educating yourself further by reading one or both of the books suggested at the beginning of this article. The implementation of an intermittent fasting regimen is most effective if utilized in the context of a low-carbohydrate, LCHF or Ketogenic diet. As always, consult your physician prior to implementing any drastic dietary changes.
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