As people age, their intestinal stem cells begin to lose their ability to regenerate. These stem cells are the source for all new intestinal cells, so this decline can make it more difficult to recover from gastrointestinal infections or other conditions that affect the intestine. This age-related loss of stem cell function can be reversed by a 24-hour fast, according to a new study from MIT biologists. The researchers found that fasting dramatically improves stem cells’ ability to regenerate.
In fasting mice, cells begin breaking down fatty acids instead of glucose, a change that stimulates the stem cells to become more regenerative. The researchers found that they could also boost regeneration with a molecule that activates the same metabolic switch. Such an intervention could potentially help older people recovering from GI infections or cancer patients undergoing chemotherapy, the researchers say.
“Fasting has many effects in the intestine, which include boosting regeneration as well as potential uses in any type of ailment that impinges on the intestine, such as infections or cancers,” says Omer Yilmaz, an MIT assistant professor of biology, a member of the Koch Institute for Integrative Cancer Research, and one of the senior authors of the study. “Understanding how fasting improves overall health, including the role of adult stem cells in intestinal regeneration, in repair, and in aging, is a fundamental interest of my laboratory.”
David Sabatini, an MIT professor of biology and member of the Whitehead Institute for Biomedical Research and the Koch Institute, is also a senior author of the paper, which appears in the May 3 issue of Cell Stem Cell.
“This study provided evidence that fasting induces a metabolic switch in the intestinal stem cells, from utilizing carbohydrates to burning fat,” Sabatini says. “Interestingly, switching these cells to fatty acid oxidation enhanced their function significantly. Pharmacological targeting of this pathway may provide a therapeutic opportunity to improve tissue homeostasis in age-associated pathologies.”
The paper’s lead authors are Whitehead Institute postdoc Maria Mihaylova and Koch Institute postdoc Chia-Wei Cheng.
For many decades, scientists have known that low caloric intake is linked with enhanced longevity in humans and other organisms. Yilmaz and his colleagues were interested in exploring how fasting exerts its effects at the molecular level, specifically in the intestine.
Intestinal stem cells are responsible for maintaining the lining of the intestine, which typically renews itself every five days. When an injury or infection occurs, stem cells are key to repairing any damage. As people age, the regenerative abilities of these intestinal stem cells decline, so it takes longer for the intestine to recover.
“Intestinal stem cells are the workhorses of the intestine that give rise to more stem cells and to all of the various differentiated cell types of the intestine. Notably, during aging, intestinal stem function declines, which impairs the ability of the intestine to repair itself after damage,” Yilmaz says. “In this line of investigation, we focused on understanding how a 24-hour fast enhances the function of young and old intestinal stem cells.”
After mice fasted for 24 hours, the researchers removed intestinal stem cells and grew them in a culture dish, allowing them to determine whether the cells can give rise to “mini-intestines” known as organoids.
The researchers found that stem cells from the fasting mice doubled their regenerative capacity.
“It was very obvious that fasting had this really immense effect on the ability of intestinal crypts to form more organoids, which is stem-cell-driven,” Mihaylova says. “This was something that we saw in both the young mice and the aged mice, and we really wanted to understand the molecular mechanisms driving this.”
Further studies, including sequencing the messenger RNA of stem cells from the mice that fasted, revealed that fasting induces cells to switch from their usual metabolism, which burns carbohydrates such as sugars, to metabolizing fatty acids. This switch occurs through the activation of transcription factors called PPARs, which turn on many genes that are involved in metabolizing fatty acids.
The researchers found that if they turned off this pathway, fasting could no longer boost regeneration. They now plan to study how this metabolic switch provokes stem cells to enhance their regenerative abilities.
They also found that they could reproduce the beneficial effects of fasting by treating mice with a molecule that mimics the effects of PPARs. “That was also very surprising,” Cheng says. “Just activating one metabolic pathway is sufficient to reverse certain age phenotypes.”
Jared Rutter, a professor of biochemistry at the University of Utah School of Medicine, described the findings as “interesting and important.”
“This paper shows that fasting causes a metabolic change in the stem cells that reside in this organ and thereby changes their behavior to promote more cell division. In a beautiful set of experiments, the authors subvert the system by causing those metabolic changes without fasting and see similar effects,” says Rutter, who was not involved in the research. “This work fits into a rapidly growing field that is demonstrating that nutrition and metabolism has profound effects on the behavior of cells and this can predispose for human disease.”
The findings suggest that drug treatment could stimulate regeneration without requiring patients to fast, which is difficult for most people. One group that could benefit from such treatment is cancer patients who are receiving chemotherapy, which often harms intestinal cells. It could also benefit older people who experience intestinal infections or other gastrointestinal disorders that can damage the lining of the intestine.
The researchers plan to explore the potential effectiveness of such treatments, and they also hope to study whether fasting affects regenerative abilities in stem cells in other types of tissue.
Fasting triggers the production of antioxidants and boosts age-related metabolites
Eating a low-carbohydrate breakfast was found to increase weight loss while eating dinner late at raised the risk of glucose intolerance and diabetes
Intermittent fasting supports weight management and reduces insulin resistance. It is not advisable to fast while eating a daily diet of processed foods
Fasting is a term that describes a variety of approaches to limiting food intake throughout a 24-hour period, or longer. One common approach is intermittent fasting, in which people limit the number of hours they eat during the day. There are a variety of approaches to intermittent fasting and no one approach is better than another.
Other people prefer doing a fast in which they do not eat for 24 hours, two or three times a month. Longer fasts are possible but they require additional support and knowledge to reduce any negative effects from a lack of preparation.
Going without food for longer periods of time was probably normal for human ancestors who did not have access to a refrigerator or restaurant on every corner. Intermittent fasting is more of a lifestyle than a diet, but ultimately, it’s a way of eating that has a significant impact on your metabolism and your health.
Fasting Actively Stimulates Metabolism
In a study published in Nature, scientists revealed data from participants who underwent a 58-hour fast. A team from the Okinawa Institute of Science and Technology Graduate University in Japan evaluated the effects of fasting by analyzing the blood of the participants beginning at 10 hours and ending 58 hours into the fast.1
During the fasting state, the body switches from burning glucose to burning fat for energy, and thus produces ketones. Other well-known by-products include butyrates, acylcarnitines, and branched-chain amino acids.2 Four volunteers signed up for the 58-hour fast, and blood was drawn at 10, 34, and 58 hours.
Some of the compounds peaked at 34 hours, while others had not yet plateaued at the end of the 58th hour of the fast. In all, they identified 44 substances that changed during the fasting period. In past studies, researchers had only identified 14.
Additionally, none of the participants was obese, since this is known to change markers during fasting. The researchers identified two butyrates that were “nearly invisible” at the 10-hour mark but had reached “major peaks after 34 and 58 hours of fasting.”3 Butyrates help maintain intestinal homeostasis by protecting the intestinal barrier and mucosal immunity.4
The researchers also identified tricarboxylic acid (TCA) cycle-related compounds that “reflect enhanced mitochondrial activity in tissues during fasting.”5 Past researchers who studied animals demonstrated that fasting can lengthen life.6 The researchers in this study were looking for “unknown health effects in human fasting.”7
Fasting Metabolites Support Antiaging
Three metabolites that decline with age include leucine, isoleucine, and ophthalmic acid. However, testing reveals that fasting individuals have higher levels of these metabolites which may help increase longevity.8
The data also revealed that during fasting, the metabolism of pyrimidine and purine was enhanced. These substances are vital to gene expression, which suggests that the practice may help reprogram protein cells and promote homeostasis. The metabolism of pyrimidines and purines affects the production of antioxidants, which researchers found significantly increased during the 58-hour fast.
They believe the data suggest that antioxidant production may be a marker of fasting that can “boost production of several age-related metabolites, abundant in young people, but depleted in old.”9 Dr. Takayuki Teruya was the first author of the paper who commented:
“We have been researching aging and metabolism for many years and decided to search for unknown health effects in human fasting. Contrary to the original expectation, it turned out that fasting induced metabolic activation rather actively.
People are interested in whether human beings can enjoy the effects of prevention of metabolic diseases and prolonging life span by fasting or caloric restriction, as with model animals. Understanding the metabolic changes caused by fasting is expected to give us wisdom for maintaining health.”
Low-Carb Breakfast Improves Weight Loss Efforts
As important as intermittent fasting is the time of day you eat your meals. For many, intermittent fasting is a way of attaining healthy weight loss they can maintain. In one study with 70 patients, researchers evaluated the difference in a morning meal that had restricted carbohydrate intake or had the same number of calories as in a typical Mediterranean-style diet.10
In the group of participants, 58.6% were women who were overweight or obese and nearly one-third had diabetes. The group was randomly assigned to one of the two breakfast meals, but the remainder of the foods in their daily diet was identical.
The average intake was between 1300 and 1500 calories per day. While both groups demonstrated improvements, by the end of the study, those who had been eating a restricted carbohydrate breakfast showed an impressive 3.5 kilogram (7.7 pounds) greater weight loss compared to the other group.
All participants in the carbohydrate-restricted group lost at least 5% of their body weight by the end of the study as compared to 65.7% of all of the individuals in the control group.
The researchers did not find other improvements in the low-carbohydrate breakfast group, including those related to glycemic outcomes. Dr. Dimitrios Tsilingiris presented the findings at the 2018 meeting of the European Association for the Study of Diabetes. In commenting on the results, he said:11
“The morning carbohydrate-restricted diet might offer certain benefits by favoring compliance…and the rapid weight lowering seen with this diet might be used in the induction of longer-term diets, or be an add-on feature in weight maintenance, even though it wasn’t tested for this.
As such, they might be helpful in the management of obesity-related type 2 diabetes. However, these diets often have limited versatility and the availability of low-carbohydrate food can impair compliance. Normally, overnight we fast and in the morning, with breakfast, our insulin rises and then drops again towards lunchtime.
As insulin drops, the fat stores tend to mobilize and act as energy substrates. Theoretically, inducing a lower insulin response after a low carbohydrate breakfast should mean we can prolong the low [overnight] insulin and fat mobilization state, resulting in a net effect on weight and fat loss.”
Eating a Late Dinner May Raise the Risk of Diabetes
What you eat and what time you eat has a significant effect on your health, specifically your risk for obesity and diabetes. A recent study published in the Journal of Clinical Endocrinology and Metabolism was led by a team from John Hopkins University.12 The researchers engaged 20 healthy young adults who spent two time periods in a clinical research unit where scientists structured the participants’ meals and sleep times.
The objective was to analyze the metabolic impact of eating a late dinner. During one time period, the participants ate a regular dinner at 6 pm, and in the second time period, they ate at 10 pm. The caloric intake of the meals was the same on both visits.13
The researchers measured hourly insulin, plasma glucose, triglycerides, and dietary fatty acid oxidation throughout the night and first thing in the morning. The participants also underwent a sleep study.
The results showed that eating dinner late at night induced higher glucose and reduced fatty acid oxidation. Senior study author Dr. Jonathan Jun said the study:14
“… sheds new light on how eating a late dinner worsens glucose tolerance and reduces the amount of fat burned. If the metabolic effects we observed with a single meal keep occurring chronically, then late eating could lead to consequences such as diabetes or obesity.
We still need to do more experiments to see if these effects continue over time, and if they are caused more by behavior (such as sleeping soon after a meal) or by the body’s circadian rhythms.”
Intermittent Fasting Improves Metabolic Health
Mounting evidence continues to reveal that what you eat and when you eat have an impact on your health. Intermittent fasting influences immunometabolism, which is the connection between metabolic health and the immune system.15
I believe it’s easily one of the most important fields in emerging medicine and supports what researchers have known — metabolic health is crucial for robust immune function.
In my interview with Dr. Paul Saladino, a board-certified psychiatrist, and board-certified in nutrition, we discussed the importance of insulin resistance which Saladino believes underlies many of the comorbidities responsible for severe COVID-19 disease. The overarching principle is that what matters most to your longevity is your immune and metabolic age, rather than your biological age.
You can see the interview and read more at “The Role of Metabolic Health in Better COVID-19 Outcomes.” While the focus of that article is on supporting your metabolic health to lower your risk for severe COVID-19, realistically, these principles are important in supporting overall good health that helps protect you against chronic and infectious diseases.
By ditching the idea of eating three meals a day in favor of trying the intermittent fasting approach, you accommodate a body that is simply not designed to be continuously fed. When you eat throughout the day, your body adapts to using glucose as a primary fuel. This encourages energy to be stored as fat and increases the risk you become progressively more insulin resistant.
Although many consider intermittent fasting as a way of losing weight, it also improves insulin resistance, increases human growth hormone production, boosts fat burning, lowers blood pressure, and boosts mitochondrial energy, efficiency, and biosynthesis. These and other health benefits to intermittent fasting I discuss in “Top 22 Intermittent Fasting Benefits.”
Take Control of Your Health With Intermittent Fasting
While it is likely that intermittent fasting is beneficial for most people, it’s important to remember a few points:
•Intermittent fasting does not have to involve restricting calories — Fasting should not make you feel weak and lethargic. The objective is to limit the number of hours that you eat.
•Sugar cravings will be temporary — As your body starts to burn fat for primary fuel, it’ll be easier to fast for as long as 18 hours and your hunger and craving for sugar will dissipate.
•Intermittent fasting is not advisable with a daily diet of processed foods — Although the process may sound like a panacea against till health, by itself it does not provide you with all the benefits. The quality of your diet plays a vital role.
If you’re new to the idea of intermittent fasting, consider starting by skipping breakfast and eating lunch and dinner within an 8-hour time frame. Make sure you stop eating three hours before you go to sleep. As demonstrated in the study mentioned earlier, eating close to bedtime can raise your glucose intolerance at night and increase your risk for weight gain.
Focus on a diet with moderate amounts of healthy protein and minimize your net carbohydrate intake by exchanging them for healthy fats like butter, coconut oil, and raw nuts. Overall, these strategies can help your body go into fat-burning mode.
It may take a few weeks, after which you’ll likely be able to fast for 18 hours and not feel hungry. By adapting to a diet of whole foods and incorporating intermittent fasting, nearly every aspect of your health will also begin to improve.
How Fasting is Boosting Cognitive Function | Thomas DeLauer
In this video, Thomas DeLauer explains that multiple research studies have shown that Caloric Restriction (CR) actually makes you smarter.
Some researchers argue that the effect of CR on cognition is only due to the weight loss and all the metabolic improvements which are associated with weight loss. However, in this study published in the journal CNS Spectrum, the researchers conducted their research in a group of 220 healthy non-obese patients, minimizing the effect of weight loss. Subjects in the CR group ate 30% fewer calories than the control group and after two years, there was an improvement in working memory in this group. The longitude and sample size of this study gives this study scientific validity.
Proceedings of the National Academy of Sciences published a similar study with 50 elderly people who stayed on a CR diet for 3 months. The study reported significant improvement in verbal memory in the CR group. Series of blood tests were also performed, and the CR group showed lower levels of C-reactive protein, a well-established inflammation biomarker, and lower fasting levels of insulin.
The detrimental effect of insulin resistance on cognition is well known as the association between insulin resistance and Alzheimer’s disease (AD) is overwhelmingly strong. Even so strong that some researchers are now calling AD a type 3 diabetes.
In a study published in Brain, Behavior, and Immunity, it was demonstrated that CR decreases inflammation of the hypothalamus by attenuating the activation of microglial cells by lipopolysaccharides (LPS).
Insulin Resistance, Cognitive Performance and the Association with AD
Once our cells become insulin resistant, this pathway is not triggered, the GLUT transporter is not situated at the membrane and glucose transport into the brain is halted. All cell types inside our brain express insulin receptors as well and again, once the receptor is resistant to insulin, glucose cannot be transported into the neuron, astrocyte, or microglia. These cells lack the energy substrate for the generation of ATP and neurodegeneration can begin as ATP is crucial for a myriad of cellular militance processes.
CR restriction is a very feasible preventive method as proved by a systematic review published by Translational Research which reported that CR or intermittent fasting is very potent interventions for increasing insulin sensitivity.
Man has long searched in vain for the eternal fountain of youth. And now, it seems, some scientists may have discovered the key to turning back the hands of time.
ABC affiliate News 15 Arizona has reported that scientists from Arizona State University and Texas A&M University have made a breakthrough discovery in plant DNA that could lead to stopping cancer cold, as well as slowing the aging process.
Centenarians are the fastest-growing segment of the U.S population, with numbers doubling every decade; by the year 2050, the number of people who will have reached the century mark is expected to pass 1 million.
Centenarians have 60% lower rates of heart disease, stroke, and high blood pressure, yet scientific explanations for their health and longevity remain elusive.
As a group, centenarians are happy and optimistic and have extremely low rates of depression and other psychiatric problems, suggesting that you may live longer by simply keeping a positive attitude.
There are four key nutrients that help prevent dementia and cognitive decline. If you want to live to be 100, you need healthy levels of vitamin D, DHA, folate, and magnesium.
To live longer, you need to counteract the progressive loss of muscle mass by increasing your protein intake as you age. The elderly, bodybuilders and endurance athletes typically have higher than normal protein requirements for their age group.
It’s also important to cycle high and low protein intake. Ideally, combine protein restriction with fasting, followed by increased protein intake on strength training days.
Fasting 16 to 18 hours each day is ideal, as this allows your body to deplete the glycogen stores in your liver to a greater degree.
The benefits of fasting are the suppression of the mammalian target of rapamycin (mTOR) and the activation of autophagy, both of which play a role in disease prevention and longevity.
In interviews and surveys with centenarians, certain themes came up time and time again when asked to explain why they’ve lived so long. Following are the 10 most common reasons they gave for their long lives:
Keeping a positive attitude
Eating good food
Participating in a moderate exercise like walking, gardening swimming, etc.
Living clean (not smoking or drinking excessively)
Having a family to interact with
Having a circle of friends
Being born with “good” genes
Staying mentally active and never stopping learning something new
Fasting is the oldest dietary intervention in the world. Modern science confirms it can have a profoundly beneficial influence on your health and longevity
Increasing your daily intermittent fasting to 20 or 21 hours will enable you to transition into more extended fasts without significant side effects. You can also ease into it using a “fat fast” or bone broth
Contrary to popular belief, water fasting is safe for most people. Groups that should NOT fast include those who are underweight or malnourished, children and pregnant or breast-feeding women
One lifestyle factor that appears to be driving not only obesity but also many chronic disease processes is the fact that we avoid ever going without food for very long. Our ancestors didn’t have access to food 24/7, and biologically your body simply isn’t designed to run optimally when continuously fed. If you eat throughout the day and never skip a meal, your body adapts to burning sugar as its primary fuel, which down-regulates enzymes that utilize and burn stored fat.
If you struggle to lose weight, this may well be a significant part of the problem — your body has simply lost the metabolic flexibility to burn fat for fuel. To correct this, you need to reduce net carbs and, ideally, the frequency of your meals. Fasting is one of the oldest dietary interventions in the world, and modern science confirms it can have a profoundly beneficial influence on your health. As noted by Fitness and Power:1
“An increasing number of researchers are saying that the intermittent fasting method is a sure-fire way for people to shred the excess fat. A study published in 2015 in the European Journal of Clinical Nutrition found that intermittent fasting gives a safe rate weight loss of 0.5 to 1.7 lbs/week, along with decreasing the overall body fat percentage.”
Research has also confirmed that many important biological repair and rejuvenation processes take place in the absence of food, and this is another reason why all-day grazing triggers the disease. In a nutshell, your body was designed to a) run on healthy fat as its primary fuel, and b) cycle through periods of feast and famine. Today, most people do the opposite.
Intermittent Fasting Versus Longer Fasts
Intermittent fasting is an umbrella term that covers many different meal timing schedules. As a general rule, it involves cutting calories in whole or in part, either a couple of days a week, every other day or even daily.2 The key is the cycling of feasting/feeding and famine/fasting. By mimicking the eating habits of our ancestors, who did not have access to food around the clock, you restore your body to a more natural state that allows a whole host of biochemical benefits to occur.
“Peak fasting” involves fasting anywhere from 14 to 21 hours each day and eating all of your meals within the remaining window of three to 10 hours. Obviously, to make this schedule work, you need to skip at least one main meal. One of the easiest ways to ease into it is to gradually push back the time you eat breakfast until you eliminate it completely and simply have lunch, then dinner.
Just be sure to eat your dinner at least three hours before bedtime. When you’re sleeping, your body needs the least amount of energy, and if you feed it at a time when energy is not needed, your mitochondria end up creating excessive amounts of damaging free radicals. Avoiding late-night eating is a simple way to protect your mitochondrial function and prevent cellular damage from occurring.
Once you’re used to intermittent fasting, you may want to consider longer fasts, where the only thing you consume is water and mineral supplements. I had previously been opposed to multiday water fasting if one was already at ideal body weight. What I failed to realize is that longer fasts provide “metabolic magic” that really cannot occur even with intermittent daily fasting.
Multiday fasting is basically akin to “taking out the trash.” It allows your body to upregulate autophagy and mitophagy to remove damaged senescent cells in your body, including premalignant cells. I believe it can be a great way to significantly reduce your risk of cancer. It’s also an extremely effective way to shed excess weight and extend your life span.
Silicon Valley Embraces Multiday Fasting
More and more people are now starting to recognize the health benefits of fasting. The strategy has quickly become popular with Silicon Valley executives, who recognize it as biohacking, opposed to mere dieting.3,4 The Guardian writes:5
“Over the last eight months [Phil Libin] the former CEO of Evernote and current CEO of AI studio All Turtles has shunned food for stretches of between two and eight days, interspersed with similar periods of eating. He’s lost almost 90 lbs and describes getting into fasting as ‘transformative.’
‘There’s a mild euphoria. I’m in a much better mood, my focus is better, and there’s a constant supply of energy. I just feel a lot healthier. It’s helping me be a better CEO,’ he said … ‘Getting into fasting is definitely one of the top two or three most important things I’ve done in my life.’ Libin is one of a growing number of Silicon Valley types experimenting with extended periods of fasting, claiming benefits including weight loss, fewer mood swings, and improved productivity.”
Another staunch advocate of multiday water fasts is Geoffrey Woo, CEO of the biohacking company HVMN (pronounced “human”). He told The Guardian: “Ketones are a super-fuel for the brain. So a lot of the subjective benefits to fasting, including mental clarity, are down to the rise in ketones in the system.”
Why Fasting Bolsters Brain Power: Mark Mattson
Contrary to popular belief, going without food for several days does not progressively deteriorate mental and physical functioning. As noted by Woo, whose experience I too can vouch for, right around the three-day mark your hunger significantly decreases and mental clarity increases, thanks to rising ketone levels. In the video above, Mark Mattson, chief of the laboratory of neurosciences at the National Institute on Aging and a professor of neuroscience at Johns Hopkins University, explains this process.
Breaking Down Myths About Fasting
Last fall I interviewed Dr. Jason Fung, a Canadian nephrologist (kidney specialist) and author of “The Complete Guide to Fasting.” Fung is a proponent of extended water fasts, especially for patients who are obese and/or Type 2 diabetic. Fung’s book provides easy-to-follow basic guidelines for fasting and reviews some of the most common myths and fears that keep many from implementing a fasting regimen.
One common myth is that multiday fasting will lead to muscle loss. The book clearly describes the process of protein catabolism, explaining how your body actually downregulates protein catabolism and upregulates growth hormones in response to fasting. As noted by Fung:
“If you follow the biochemistry, your body stores energy as glycogen in the liver, which is links or chains of sugar, and then it stores [it as] body fat. During fasting, you start by burning off all the glycogen in the liver, which is all the sugar. There’s a point there where some of the excess amino acids in your body need to get burnt as well.
That’s where people say, ‘That’s where you’re burning muscle.’ That’s not actually what happens. The body never upregulates its protein catabolism. Never is it burning muscle; there’s a normal turnover that goes on. There is a certain amount of protein that you need for a regular turnover. When you start fasting, that starts to go down and then fat oxidation goes way up. In essence, what you’ve done is you switched over from burning sugar to burning fat.
Once you start burning fat, there’s almost an unlimited amount of calories there. You could go for days and days. What’s interesting is that if you take a pound of fat, that’s roughly 3,500 calories. If you eat somewhere around 1,800 to 2,000 calories a day, it takes two full days of fasting to burn a single pound of fat, which is very surprising to people.
If you’re trying to lose 100 pounds, you could theoretically go 200 days of fasting just to burn all that fat … People worry about fasting for 24 hours. I’m like, ‘You could go 200 days.’ Then it’s like, ‘OK. Maybe it’s OK to go 24 hours without eating.'”
The Man Who Fasted for 382 Days
It has been my observation that most people fear to fast, thinking they will be unable to tolerate the suffering, but as Fung says, an obese individual could theoretically go without food for months without starving to death. The 1965 medical case of a 27-year-old man who fasted for 382 days is a powerful case in point.6,7 When he started, he weighed 456 pounds. In the end, he’d lost just over 275 pounds, and five years after breaking his fast, he’d gained back a mere 11 pounds.
Please understand, I am not recommending months- or yearlong fasts. This man was under strict medical surveillance, and you should be too if you’re planning on fasting for an extended period of time. He took multivitamins and potassium daily, and I recommend taking a high-quality multimineral supplement any time you do a water-only fast. What’s so interesting about this case is that it clearly demonstrates that extreme fasting can be safely done.
Provided you’re not anorexic, old and frail, pregnant or have some other serious health issue, fasting for three to seven days is not going to kill you. This case also demonstrates that loss of muscle mass is an overrated concern. ABC Science, which reported the case, notes:8
“After two or three days of fasting, you get your energy from two different sources simultaneously. A very small part of your energy comes from breaking down your muscles — but you can avoid this by doing some resistance training … The majority of your energy comes from breaking down fat.
But very soon, you move into getting all your energy from the breakdown of fat. The fat molecules break down into two separate chemicals — glycerol (which can be converted into glucose) and free fatty acids (which can be converted into other chemicals called ketones). Your body, including your brain, can run on this glucose and ketones until you finally run out of fat.”
Why Fasting Improves Rather Than Depletes Energy
Another major concern is that fasting will leave you physically drained and lethargic. While you may certainly feel less than optimal during the first few days the first time you do it, fasting actually tends to have the complete converse effect on energy levels. As explained by Fung:
“[A]fter four days of fasting, the basal metabolic rate is actually 10 percent higher than when you started. The body has not shut down at all. In fact, what it’s done is it switched fuel sources. It switched from burning food to burning [body] fat. Once it’s burning [body] fat, it’s like, ‘Hey, there’s plenty of this stuff.'”
In other words, if you’re overweight and lethargic, fasting helps unlock energy already lodged in your body that you previously had no access to. Fasting forces your body to start accessing those stores of energy, and once that happens, your body suddenly has a near unlimited supply of energy! Insulin plays a role here as well. Insulin is the primary hormone that tells your body whether to store energy or burn it.
When you eat, you’re taking calories in and insulin goes up. Higher levels of insulin signal your body to store energy. When insulin falls, it tells your body to release energy, i.e., the energy stored in your fat cells. This is why it’s so difficult to lose weight when you’re insulin resistant.
Fasting also helps improve other biochemical systems in your body. There’s an interplay of hormonal systems like the mammalian target of rapamycin (mTOR), AMPK, leptin, and IGF-1 — all of which are optimized in the right direction when fasting. It also improves your mitochondrial function, allowing your mitochondria to regenerate.
How to Ease Into Multiday Fasting
While the idea of fasting for several days may seem daunting, there are ways to ease into it that will minimize any discomfort. The way I graduated into four-day fasting was by increasing my intermittent daily fasting from 16 hours (which I did for 18 months) to 21 hours, leaving only a three-hour window in which I ate all my food for the day. After two months of that, I did a four-day fast where my only sustenance was water and a multimineral supplement.
I don’t think you need to do intermittent fasting for 18 months before trying water-only fasts, but doing it for a few months would radically decrease any negative side effects. I experienced no hunger pains whatsoever, which I find fascinating as most people who fast are really hungry by the second day. I believe getting used to 21-hour daily fasting had a lot to do with that.
So, if you want to try a multiday fast, consider extending your intermittent fasting first, then work your way into 24-, 48-, 72-hour and even longer fasts. And remember, you are in complete control and can break your fast any time you want.
In fact, one of the major benefits of extended fasting is an increased sense of self-control and freedom. Once you finally understand that you can easily go for days without food, you’re no longer a victim of your surroundings. If you’re traveling and cannot find healthy food, you don’t have to resort to junk food. You can simply go without. If you’re in a disaster situation, you can rest easier knowing you can handle a temporary food shortage without losing your mind.
After four days of water fasting, I’d lost 10 pounds, primarily from cleaning out my colon and expelling water attached to glycogen, i.e., “water weight.” In the end, my ketones were 5.1 and my blood sugar 45, which is double the ketone/glucose index threshold Dr. Thomas Seyfried says is necessary to treat cancer. After the fast came the feast. Upon breaking my fast, I had 130 grams of net carbs with sweet potatoes and fruits and extra protein.
Variations of Fasting
You also have a number of other options that can help ease you into an extended water-only fast. The following are some of the most common variations:
•Water plus noncaloric beverages. A slight variation on the water fast is to include other noncaloric beverages, such as herbal tea and coffee (without milk, sugar or other sweeteners, including artificial non-caloric sweeteners).
•Bone broth variation. Another variation Fung often recommends for longer fasts is to allow the use of bone broth. In addition to healthy fats, bone broth also contains lots of protein, so it’s not really a true fast. Still, in his clinical experience, many who take bone broth in addition to water, tea and coffee experience good results.
•Fat fasting. Here, you allow healthy fats during the fast in addition to water and/or noncaloric beverages. While you probably would not eat a stick of butter, you could have bulletproof coffee (black coffee with butter, coconut oil or MCT oil), for example. Alternatively, you could add the fat to your tea.
Dietary fat produces a very minor insulin response, and since you’re keeping your insulin levels low, you’re still getting most of the benefits of fasting even though you’re consuming plenty of calories. Adding healthy fats such as butter, coconut oil, MCT oil, and avocado can make fasting experience a lot easier.
My personal assistant, who tried a water-only fast, complained of severe fatigue three days in. While this is a normal response in the initial stages, I made her a “fat-bomb drink” with some coconut oil, MCT C8 oil, butter, and a little stevia, which perked her right back up.
The key is to avoid protein as it activates mTOR, and may actually be more metabolically damaging than excess carbs. While the level of protein at which you’ll counteract the benefits of fasting varies from person to person, you’ll likely see results as long as you stay below 10 or 20 grams of protein per day.
Important Contraindications and Cautionary Advice
While most people would likely benefit from water fasting, there are several absolute contraindications. If any of the following apply to you, you should NOT do extended types of fasting:
Underweight, defined as having a body mass index (BMI) of 18.5 or less.
Malnourished (in which case you need to eat healthier, more nutritious food).
Children should not fast for longer than 24 hours, as they need nutrients for continued growth. If your child needs to lose weight, a far safer and more appropriate approach is to cut out refined sugars and grains. Fasting is risky for children as it cuts out ALL nutrients, including those they need a steady supply of.
Pregnant and/or breastfeeding women. The mother needs a steady supply of nutrients in order to assure the baby’s healthy growth and development, so fasting during pregnancy or while breast-feeding is simply too risky for the child.
I would also caution you to avoid fasting if you struggle with an eating disorder such as anorexia, even if you are not clinically underweight. In addition to that, use caution if you’re on medication, as some may need to be taken with food. This includes metformin, aspirin and any other drugs that might cause stomach upset or stomach ulcers. Risks are especially high if you’re on diabetic medication.
If you take the same dose of medication but don’t eat, you run the risk of having very low blood sugars (hypoglycemia), which can be very dangerous. So, if you’re on diabetic drugs, you must adjust your medication before you fast. If your doctor is adverse toward or unfamiliar with fasting, you’d be wise to find one that has some experience in this area so that they can guide you on how to do this safely.
Multiday Fasting Is a Powerful Biohack for Health and Longevity
I will be interviewing experts on fasting in the future to go into more detail of all the benefits provided by extended water fasts, but until then, I would encourage you to increase your daily intermittent fasting toward the 18- to 21-hour range, which will enable you to transition into more extended fasts without significant struggle. If you are on medication or have a chronic health condition, work with your doctor to make sure you don’t complicate your situation.
For example, you need to make sure you’re taking a high-quality multimineral supplement daily. Ideally, educate yourself about the process before you get started. Fung’s book, “The Complete Guide to Fasting, “9 is an excellent resource. Also, before you jump into dayslong water-only fasting, start with intermittent fasting. I believe it will significantly ease the process and raise your chances of success.
If you were to look up “autophagy” online, you would see that it has become the latest fascination and health cure over the last few years. It is most commonly associated with one of the benefits of a ketogenic diet and fasting. Currently, there are many claims to its fame, including extending life, slowing the aging process, and acting as a natural detox to your system. There is positive scientific evidence to show how you can use autophagy to clear damaged cells from your body and reduce inflammation.
History of Autophagy’s Discovery
Autophagy was first discovered and named by Christian de Duve, a 1974 Nobel laureate. He discovered the lysosome. Upon continued observation of lysosomes, he discovered damaged or unusable material placed into the lysosomes. Therefore, he coined that process autophagy, or “self-eating,” and called the cellular transportation vehicles autophagosomes.
In 1988, a gentleman by the name of Yoshinori Ohsumi started his own study related to autophagosomes. During his experiments, he chose to interrupt the process of autophagy in a cell in order to hopefully create a larger gathering of autophagosomes. By doing so, he hoped to be able to view them better under the microscope. The method he chose to do this was by starving the cells, and surprisingly, it worked! Ohsumi discovered a method to identify and characterize key genes involved in autophagy. The results were published in 1992, and in 2016, he was awarded the Nobel Prize in physiology.
Definition of Autophagy and Its 3 Types
As stated above, autophagy is Greek for “self-eating.” Simply put, it is defined as the process in which misfolded proteins, damaged organelles, and pathogens are transferred into lysosomes to be broken down and then recycled for cellular use – similar to how we collect plastic bottles, smash them down, and then re-create other plastic materials.
There are 3 types of autophagy:
1) Macro-autophagy – delivers cellular “garbage” to the lysosome by an autophagosome and then fuses with the lysosome to create an autolysosome.
2) Micro-autophagy – the lysosome itself absorbs the damaged cells.
3) Chaperone-mediated autophagy – the degraded cellular material essentially rides “piggyback” on a protein which the lysosome receptors recognize and then that protein is unfolded and degraded.
Can autophagy help clear damaged cells from your body?
The role of autophagy in our bodies helps maintain the homeostasis of our cells. We have various amino acids and proteins which act as fuel for our cells. Some of those proteins don’t develop as they should or get used and discarded by our organs. The process of autophagy causes our lysosomes to absorb these organelles and proteins; they then break them down and convert them into usable cells for our body once again.
Most studies regarding this process were performed while starving the cells – literally. The subject’s body did not receive food for 24-48 hours. This creates both a further breakdown of protein cells and an increase in amino acids which then cause the cells to group together faster while elongating and enlarging. This makes it easier for the lysosomes to absorb and recycle.
We must remember that we are only as healthy as our cells are. By starving the cells, they kick into survival mode by attempting to create more food through amino acids in order to ensure our tissues and organs remain operational. At the same time, they cannot allow this sudden abundance of “bad cells” to remain in our body and therefore must attach themselves to lysosomes in order to rid the body of this excess – much like we do not allow trash to accumulate in our homes for an extended period of time.
We naturally fast on a daily basis from the time we eat dinner until we eat breakfast the next morning. This assumes, of course, that you aren’t getting up to eat or snacking prior to sleep. If you eat dinner by 6 and then don’t eat breakfast until about 7 – 8 a.m., then you have fasted for 13-14 hours. While most studies were done on subjects who fasted for 24-48 hours, results manifest in 14-16 hours. Scientists have also stated that fasting for 2-5 days or reducing calorie intake has shown to trigger autophagy.
Exercising is another way scientists theorize that autophagy can be triggered. This is still being studied. Scientists believe that autophagy is the reason behind all the chemical benefits that occur in your body after exercising. There exists evidence of increased life span and protection against cardiovascular diseases, diabetes, cancer, and neurodegenerative diseases. These benefits mirror the results scientists are seeing in their studies about autophagy. Additionally, they discovered increased cognitive function in the cerebral cortex due to increased activity of autophagy after exercise.