*Note to the reader: This is not medical advice. If you are considering 'fasting' please consult a health care professional before attempting.
You need to eat every few hours, otherwise, your blood sugar will drop, you’ll get cranky and your body will enter starvation mode. If you don’t, you’ll gain weight, your brain will get foggy, and you’ll have reduced performance mentally and physically.
So, make sure you eat small meals every three hours and snack often.
Have you heard this before? My mom used to tell me something like this, and doctors, magazines, and everyone in the fitness industry (ever see bodybuilders dragging1 coolers full of food?) echoed her ‘wisdom.’
When did frequent eating become so important to human health? Did our ancestors use sundials to time out their scavenged roots and dried meat snacks? Not likely. The truth is quite the opposite. Frequent meals is a modern notion.
The evolution of mankind has been rocky at best, and food security has always been a struggle (and for many still is). Mark Mattson, head of the National Institute on Aging's neuroscience laboratory, believes that, "evolutionary pressures selected for genes that strengthened brain areas involved in learning and memory, which increased the odds of finding food and surviving.”2
In other words: you had to be smart to survive, and in past times that often meant thinking on an empty stomach.
Our evolution through times of famine and scarcity has taught our body to function at its highest levels in the absence of food. Even at the most basic level, the way our body uses and stores food is built around the idea of surviving and thriving without food.
That spare tire you hate? Your body spent millennia developing the ability to create that. It ensures that if you had to survive a harsh winter, your body would have its own internal fuel source.
But, you’re not likely preparing for a hard winter of scarce food. Therefore, the potbelly has lost its true purpose. But are there reasons why you should simulate a rough winter and skip some meals, or go days without eating?
New research is challenging many of the misconceptions around meal frequency and timing. Some researchers are bold enough to claim that instead of searching for superfoods and supplements, eating nothing might be the most powerful tool for healing our bodies.
The Health Benefits of Fasting
A number of health benefits have been attributed to fasting, all of which are controversial to say the least.
Those who argue against fasting highlight that much of the research has been done on animals and that in human studies, most if not all the benefit come from eating in a slight caloric deficit (which is common when fasting).
The science is by no means settled, but there has been research showing significant benefits from a period of no or restricted eating.
Studies have shown fasting may improve the following:
A 2017 study in the Journal of American Medical Association, which looked at alternate day fasting found that it “works roughly as well for weight loss as traditional dieting does.”
‘Traditional dieting’ means eating in a caloric deficit consistently for a period of time. The fasting group in the study would eat very low calorie on fasting days and then on eating days would enjoy a calorie surplus (#cheatday).
So, when it comes to weight loss, fasting is just as good as the average diet, but there might be additional benefits.
Dr. Jason Fung MD, who’s written extensively on fasting, has highlighted that fasting helps with a common problem of weight loss -- excess skin. He says that, if you do a long term fast, “your body will burn the excess proteins of flabby skin left over from weight loss.”3
Beyond your waistline, fasting may positively affect your mood. According to a study in Psychiatry Research, “Clinicians have found that fasting was frequently accompanied by an increased level of vigilance and a mood improvement, a subjective feeling of well-being, and sometimes of euphoria.”4
This might sound counter intuitive to most people's perception of going without food (hangry much?). But these are the findings.
It should be noted that it often takes time for bodies to adapt to fasting. Many of the benefits might not be seen immediately or during the first period of fasting. This is important to be aware of when experimenting.
Ever heard of starving a fever? There might be some science to back up the adage. A 2016 study looking at mice infected with bacteria found that, “After 10 days all the bacteria-infected mice who had continued being fed had died, while more than half that had avoided food lived.”5
Human studies have yielded similar results. A 2002 study found that, “...eating stimulates the kind of immune response needed to combat viral infections, while fasting might stimulate the immune response that takes down unfriendly bacteria.”6
The benefits of fasting on the immune system may even be helpful when you aren’t already sick.
A 2014 study at the University of California found that fasting for 3 days, “‘flips a regenerative switch’ which prompts stem cells to create brand new white blood cells, essentially regenerating the entire immune system.”7
This has huge implications for those with reduced immune function due to disease or ageing.The same study also found that, “prolonged fasting also reduced the enzyme PKA, which is linked to ageing,” meaning fasting might help you live longer.
Immune function is important, but it seems fasting may have an even greater impact when the body is under extreme periods of stress like when fighting cancer.
“The mouse study on skin and breast cancers is the first study to show that a diet that mimics fasting may activate the immune system and expose the cancer cells to the immune system,” said the Study's author Valter Longo.
He continues, “This could be a very inexpensive way to make a wide range of cancer cells more vulnerable to an attack by the immune cells while also making the cancer more sensitive to the chemotherapy.”
Longo’s findings build upon prior findings which showed that a short-term fast can actually starve cancer cells while also helping chemo drugs to better target the cancer.8
(There is a much longer list of research on possible benefits way too long for this article, but I encourage you to look into them if this topic interests you.)
Types of Fasting
"Alright, stop throwing science at me, what exactly does fasting mean? How many meals do I eat? How long do I wait until eating again?”
Fasting is also known as ‘time-restricted eating’ or ‘intermittent fasting.’ Each of us fasts naturally throughout the day between meals and when we sleep. The fasting we’re talking about here is when you extend those periods beyond 8 hours.
There are one-off fasts or ‘fasting events’, for example, you just don't eat for 1-10 days. These can be done monthly or quarterly or at whatever interval you prefer.
But others implement the benefits of fasting into their everyday life and have created routine fasting rituals. Here are some of the most common protocols for fasting:
Alternate day fasting (ADF) -- (36-hour fast/12-hour feed)
With this plan, you simply eat every other day. So, Monday you’d wake up, eat your first meal at 8 am and stop eating at 8 pm. You’d then eat nothing on Tuesday. Wednesday morning you’d eat 8 am until 8 pm again.
This plan works well for those who live low-activity lives.
Meal-Skipping -- (Random)
The idea behind this diet is to live like our ancestors. As humans, we evolved getting our food and exercise randomly.
Basically, you throw chaos into your diet. Sometimes you eat nothing, sometimes eat a lot, but you never create predictability.
This work well for someone who hates ritual and lives a spontaneous life, but it’s hard to track the benefits.
Eat Stop Eat - (24-hour fast, 1 or 2 times per week)
This plan is simple and popular. Essentially, you just choose 1 or 2 days a week not to eat. So, you eat regularly all week. Then on Sunday, you’d eat nothing. This diet works well with athletes (such as when in a calorie surplus to ward off fat gain.)9
Leangains - (16-hour fast/8-hour feed)
This style of fasting is most common in the bodybuilding and fitness world. Each day you restrict your eating to an 8-hour window.
So, Monday you’d wake up and eat your first meal at 8 am. Your last meal would be at 4 pm, and then you don’t eat again until Tuesday at 8 am.
You repeat this 7 days per week. This is likely the easiest form of fasting, as many people incidentally do this by skipping breakfast.
Warrior Diet -- (20-hour fast/4-hour feed)
This is similar to ‘leangains’ mentioned above, except the eating window is shortened to 4 hours. Most followers place the eating window in the evening, as turning down dinner meal invitations is much harder than breakfast and lunch. You still want to enjoy life, after all.
So, you’d only eat between 4 pm and 8pm and wouldn’t eat until the following day at 4 pm. This is followed 7 days per week.10
Potential Health Risks of Fasting
“According to the UK's National Health Service (NHS), there are numerous health risks associated with intermittent fasting.”11
It’s common for people fasting to become dehydrated as people forget that food contains significant amounts of water, which needs to be replaced when not eating. This dehydration can then lead to further issues including increased stress and reduced sleep.
Dehydration also can become key, because if you’re not eating and are just drinking plain water you will be taking in no electrolytes which can further exacerbate the symptoms of dehydration.
This can cause headaches and sleep deprivation. In his book Tools of Titans, Tim Ferriss explains how this danger can play out and that if you drink only water you may be unable to sleep “due to electrolyte depletion and subsequent cholinergic responses (e.g., rapid heart rate when trying to sleep)”.12
Fasting may also cause heartburn. The lack of food will naturally cause a decrease in stomach acid but if you’re surrounded by others who aren’t fasting, just the smell of food or even sometimes thinking about food can cause the stomach to produce more acid, which may lead to heartburn.
In addition, it’s common for there to be some muscle loss on a fast depending on how quickly the body enters ketosis. Tim Ferriss explains how he lost 12 pounds of muscle in his first 7-day fast.
This doesn’t mean muscle loss is required. If done properly, you can reduce and even stop muscle loss. When Ferriss did another 10-day fast with a new protocol he lost zero muscle mass. (Tim’s exact protocol can be found here)
It’s also well documented that long term hypocaloric diets (calorie deprivation) can harm your metabolism and cause serious muscle wasting. Do not confuse fasting with anorexia. Long term calorie deficient diets will cause your metabolism to down-regulate and may cause paradoxical effects such as weight gain.13
Most of the side effects of fasting are very short term while the body is adapting to the fasted state.
My Personal Experience
Personally, I love putting new ideas to the test. I’m no Dave Asprey, but I do enjoy experimenting with my body to find out what works for me.
I’ve attempted three fasting methods and I’ll review my experience below:
The first was Intermittent Fasting -- eating all of my calories within a 8-10 hour period -- which has become my go to method. I’m not as consistent as I’d like to be, but I find this method the easiest way to maintain a fasting practice.
Generally, I won’t eat until 10am or 12pm. Then, I’ll stop eating at 8pm. For me, this one worked well to help maintain a healthy body weight.
I played football as an offensive lineman from the age of 9 to 24, and at my heaviest, I weighed 300 pounds. After my last season at McMaster University it took me about a year to reach 205 pounds. But, this weight is difficult to maintain because my body quickly absorbs calories whenever it gets the chance.
I find intermittent fasting makes it easier for me to maintain a healthy body weight. The only downfall with this method is I find it difficult to time my workouts for meals. I typically hit the gym by 11am and generally like to be hydrated and have a meal before I do. I find my workout intensity suffers when I exercise in a fasted state.
The second method I’ve used is fasting for a 24-hour period once per week. As mentioned before, the hunger you feel only lasts a few hours after skipping your first meal. After that, I typically have good energy and mental clarity. When I’m feeling extra peppy, I try to do a fasted weight lifting session. I’ve seen some evidence that lifting in a fasted state can increase growth hormone production. As a guy in his late 30’s who wants to maintain muscle mass, I, of course, welcome a little spike in GH.
And the third method is to completely fast for three-days, which I recently finished. My experience was typical based on other accounts I’ve heard. Day one wasn’t too bad. The hunger and food cravings left a few hours after waking up. For the rest of my day, I felt a bit weak and low energy but my mental cognition seemed to be firing on all cylinders and I had a flow of creative ideas streaming in all day.
Day two was harder. I woke up at 3:30 am and couldn’t get back to sleep. All morning I experienced headaches, low energy, and mental fog. I kept up with my endless stream of emails, but that was all I could get done.
At 12pm I went for a float and had a deep and restful experience, which helped for the rest of my day. That night, I took my favorite nootropic supplement, Brain Evolve, and slept like a baby.
Day three was fantastic. I woke with no hunger, and my energy and mood were high. I had creative insights flowing all morning and made good use of my pen and note pad. At 1 pm, I conducted a mapacho (black amazonian tobacco) ceremony on Wreck beach (something I do weekly).
Sitting in stillness, I let all the reflections and insights of the past two days flow. I analysed my state of being and enjoyed a hour-long meditation in nature. A few people recommended that I should continue for a few days after, as the first 3 days are the hardest.
There’s some evidence showing that other health benefits begin after three days, like digesting unhealthy cells as energy, but I was concerned about muscle loss at that point. So, I elected to break my fast that night at supper with a homemade bowl of Pho Ga.
After it was done, I definitely lost a few pounds. It felt as if my GI (gastrointestinal) tract was thoroughly cleansed. But, the best part was that I felt as if my cravings had reset, meaning I no longer had the food cravings I normally would.
My conclusion based is that fasting is a good method for spring-boarding into a healthy, well-balanced diet. It’s a tool I will continue to implement as a health practice.
I’ll most likely continue intermittent fasting as a habit -- that said, I’ll allow myself the grace to be kind to myself. If I fall off the habit, I won’t beat myself up for lack of discipline. I’ll most likely reserve the three-day fasts to an every 4-6 week practice.
There’s no consensus in the medical world as to the benefits of fasting. It’s important to remember that this area of research is young and that as it matures we’ll get a better picture of the mechanisms involved in fasting and its effects.
It is clear that some people have experienced verifiable benefits from fasting. With that in mind, it is clear the advice would mirror that of any diet prescription. Try it out. Try doing a few different types of fasting, do it properly, give it time to settle in and see how your body and mind respond.
Some people will become immediate converts. Others will say ‘not for me’. No matter what the doctors and researchers say, nothing will ever replace the importance of trial and error and listening to your own body.
I’d say try fasting at least once if for no other reason than to prepare for a possible zombie apocalypse.
Written by: Andy Zaremba
Andy Zaremba is a leader in the human consciousness and optimization communities. Located in Vancouver, B.C. In 2013, Andy and his brother Mike, partnered to create the Float House franchise, Canada’s leading flotation therapy centres, which now have eight locations across Western Canada.
In addition, Andy co-hosts (again with brother, Mike) the Vancouver Real podcast, a digital media leader in the human consciousness space. The podcast has produced over 125 episodes with incredible guests such as Dr. Gabor Mate, Graham Hancock, Rick Doblin, and Wim Hof to name just a few.
Personally, Andy is father to Ella Faith, his seven-year-old daughter, whose miraculous birth and survival have been key to Andy’s personal growth and dramatically changed the trajectory of his life. In fact, it was during her ten months’ post-birth in the NICU and following two years with full time home care when Andy began his practice of mindfulness meditation, yoga, and self-education through podcasts. This eventually led him to launch both Float House and Vancouver Real podcast.
Andy is living his vision helping to facilitate the expansion of human consciousness worldwide. His interests include traveling, fitness, martial arts, yoga, plant medicine, meditation, music, art, hiking, scuba diving, and stimulating conversation.