[0:00:51] Podcast Sponsors
[0:03:50] My Fasting Q&A Introduction
[0:07:27] How does fasting for longevity differ from fasting for things like fat loss or circadian rhythm?
[0:16:49] Does coffee hurt or harm your fast?
[0:18:08] Podcast Sponsor
[0:20:00] How fasting can affect your sleep?
[0:23:42] Hormonal effects of fasting in men vs. women
[0:30:46] Does fasting slow down your metabolism?
[0:33:23] Tips for Enhancing the Benefits of a Fast
[0:36:26] The Best Types of Training to Engage in While Fasting
[0:38:53] How to Properly Prepare for And Break an Extended Fast
[0:42:18] Is it okay to fast while breastfeeding or pregnant?
[0:45:37] Does your ability to absorb food and supplements increase after a fast?
[0:48:14] Essential Amino Acids' Effect on Fasting
[0:52:35] Gastrointestinal Effects and Dry Mouth During Amino Acids
[0:55:42] Closing the Podcast
Ben: I have a master's degree in physiology, biomechanics, and human nutrition. I've spent the past two decades competing in some of the most masochistic events on the planet from SEALFit Kokoro, Spartan Agoge, and the world's toughest mudder, the 13 Ironman triathlons, brutal bow hunts, adventure races, spearfishing, plant foraging, free diving, bodybuilding and beyond. I combine this intense time in the trenches with a blend of ancestral wisdom and modern science, search the globe for the world's top experts in performance, fat loss, recovery, gut hormones, brain, beauty, and brawn to deliver you this podcast. Everything you need to know to live an adventurous, joyful, and fulfilling life. My name is Ben Greenfield. Enjoy the ride.
Today is the fasting episode question-and-answer session. If you like fasting, you don't want to miss this one. Before we jump into the show though, I have to tell you that I'm pretty excited and I don't know why I'm talking like this. The brand new flavor of the amino acids that rules all other amino acids and kicks the butt of all other amino acids in terms of flavor, amino acid ratios, the ability to build muscle, the ability to be able to repair the gut, to keep your appetite satiated, one of the few supplements that I take every single freaking day; well, we just added in addition to the cool lime flavor of these amino acids, the berry flavor. Yeah, that's right. We got a brand new berry aminos. It just went live, literally. Just went live. You got to taste this stuff. Tastes like, as I'm prone to say, crack cocaine, if crack cocaine could taste. Anyways, you can get it right now over at getkion.com. It's flying off the shelves. It's the brand new Kion Aminos. And did I mention? It's perfect for fasting. Helps you to maintain muscle and stay in a fasted state. How cool is that?
This podcast is brought to you by Kion. So, getkion.com. This podcast is also brought to you by something really cool. You've heard me talk about using infrared light and red light therapy on your bowels, guys, on your skin cellulite. I was going to say ladies but guys have cellulite too. I know some guys with some really gnarly cellulite, actually. It can be used on the thyroid gland. It can be used to enhance sports performance because you get nitric oxide released into your bloodstream after you use it. I'm talking about the light that is specifically the Joovv light.
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Well, hello. Welcome to my Q&A, my living room fireside chat. I don't even know what a fireside chat is. It's very seldom that I have started a fire and sat down next to it with someone and chatted with them, but I can only imagine that if I had two giant lazy boys in my living room with a roaring crackling fire, perhaps some chestnuts or whatever the hell you do when you're sitting by the fire, I could have more fireside chats. But regardless, the fireside chat thing is apparently pretty dang good. So, I'm going to describe today's podcast as a fireside chat.
It's actually a fasting Q&A, not a fireside chat. But I have gotten so many questions about fasting that I thought I would just get onto a solosode, as I'm prone to say, and answer all of your questions because we kicked off the year over at my company, Kion, with a five-day fast in which we had over 10,000 people participating in everything from a fasting mimicking diet to an intermittent fasting protocol, to a strict five-day water fast, to an elemental diet. And during that process boy, oh boy, did I get a lot of questions.
As a matter of fact, I thought the, “Will this take me out of keto?” question was kind of a little bit of an overcooked question on Twitter, so to speak. Someone will text me a photograph of gum and say, “Will this take me out of ketosis or perhaps a cigarette? Will this take me out of ketosis?” Two sticks of butter and their morning cup of coffee, “Will this take me out of ketosis?” And it turns out I was wrong. A more common question is a, “Will this take me out of a fasted state? Will coffee take me out of a fasted state? Creatine? Fish oil? Hugging my grandmother good morning?” Anything. And so, not only did we get that but here's a sample of the questions I'm going to be answering during today's episode, and then I'm just going to shut up and jump in.
Does coffee hurt or harm your fast? What to do if you don't sleep well on a fast? What is the hormonal effect of fasting on males or for females? What's the best kind of fasting if you want to gain muscle versus if you want to lose fat? Do extended fasts slow your metabolism? And if so, what can you do about that? What kind of training or exercise is best when fasting? What things can you do to enhance the benefits of a fast like cryotherapy or a coffee enema? Will a coffee enema take me out of ketosis? No, I'm just kidding. How should you prepare for a fast and how should you break a fast? Is it okay to fast while breastfeeding or pregnant? Does your ability to absorb foods and supplements increase after a fast?
And then amino acids and fasting. I've got a lot of questions about amino acids and fasting. So, I will be answering all those questions and going down a lot of rabbit holes during today's episode. So, if you're ready to sit back, eat nothing at all, please, accept the gum and the buttered coffee, and sitting by your fireside with your grandmother. Let's go ahead and jump in. And everything I'd talk about, everything, I will create comprehensive shownotes for if you just go to BenGreenfieldFitness.com/fastingQA. That's BenGreenfieldFitness.com/fastingQA.
And so, without further ado, let's just jump into the first question. Here we go. I shall read it and then reply to it. My first few replies may be longer than my others because I'll want to lay down some science, speak to allow you to understand my replies to other questions. So, the first question is this, “How does fasting for longevity differ from fasting for other reasons, like fat loss or circadian rhythm?”
Well, this comes down to the idea of fasting for longevity, being synonymous to fasting for what's called autophagy. And what I want to do is just explain the basic physiology of what's going on here when you are fasting for longevity. We know that research shows that calorie restriction, specifically reducing your calories not completely by reducing them about 20% to 40%, that's the most effective way to regulate aging and increase lifespan. And it's simply been shown over and over and over again that fasting can do three things really that allow this to happen; inhibit what's called the mTOR pathway, and then also stimulate autophagy and induce ketogenesis.
So, autophagy, that's a word that literally means self-eating or auto-eating. It was discovered in yeast quite some time ago, and it was later learned that this is a fundamental part of all human cells. Autophagy should not be confused with what's very similarly kind of thrown around in science but that I think is inaccurately thrown around. That's apoptosis. Okay. Apoptosis means that the entire cell is killed off. That's a programmed cell death and defects in it can contribute to cancer where there's no apoptosis, so cell accumulation occurs or neurodegeneration where rampant apoptosis kills off neural cells.
So, rather than killing off the entire cell, autophagy occurs when the body just replaces some parts of that cell. So, you think of this as like spring cleaning for the cells, so you get rid of old membranes and organelles and cellular debris, and you send them via something called autophagosomes or autophagosomes, depending on how you pronounce it, to what are called lysosomes, which are organelles that contain these protein degrading mechanisms that then get rid of this cellular debris.
So, during autophagy, your oldest, most worn-out cellular parts get discarded and then amino acids from the broken-down cell parts either go to your liver to allow you to make glucose, or they get incorporated into new proteins. And cleaning up all that junk has been shown to do things like suppress tumors and support immunity and allow for better cellular development and differentiation. A defective autophagy has been linked to cancer and autoimmune disease and neurodegenerative disease and accelerated aging.
So, the idea is that eating shuts down autophagy. Eating shuts down autophagy, and fasting increases autophagy. The idea here is quite simple; if you somehow figure out a way to allow your body to engage in that natural cellular cleanup and it begins to kick in in as little as 12 hours and can continue to kick in with these longer fasts, then you're going to increase that natural cellular clean up.
Now, the other term you want to be familiar with is an enzyme termed mechanistic or mammalian. There are two different ways that it's often thrown around, but its mechanistic target of rapamycin or mammalian target of rapamycin. So, it's thankfully just shortened as mTOR. You have two different mTOR pathways. One's called mTORC1, one is mTORC2. Now you can think of mTOR as an energy enzyme. It transfers what's called a phosphate group. So, ATP, which is the energy currency that keeps your cells going, becomes ADP. And mTOR manages the processes that generate or use a large amount of energy like cell growth or protein synthesis or autophagy.
When mTOR is activated, autophagy, which I just got done describing to you, is suppressed. And when mTOR isn't activated, which occurs when you fast, autophagy increases. Okay. So, basically, mTOR is inversely correlated to autophagy to a certain extent. So, every time you eat, you activate mTOR and you suppress autophagy because activation of mTOR increases your insulin and your amino acid levels and that can decrease the amount of cellular autophagy that's going to occur. And of course, you could look at this the other way. You could say if you want to get anabolic, huge, put on a lot of muscle, you'd want to keep mTOR activated. Research has shown over and over again that fasting reduces mTOR activation. And very much like autophagy, mTOR serves a purpose, but too much of it or too little of it can create problems. So, you want this press pulled cycle between activating mTOR and restricting mTOR.
And then finally, in addition to autophagy and mTOR being linked with fasting, there's this idea of ketosis, which occurs when your body utilizes fat, more specifically ketones derived from burning fat as the primary source of fuel. And when ketones are burnt as a primary source of fuel, we see less oxidative stress, which can slow the aging process. Are there ways to do that aside from strict ketosis? Absolutely. Lowering glycemic variability, eating a diet rich in legumes and other slow-release carbohydrates, avoiding starches and avoiding sugars. I'm not saying you need to be in strict ketosis, but enabling your body to be able to limit oxidative stress by reducing glucose throughput is a good idea. Okay. And we know that fasting does all these things; it can increase ketosis, it can inhibit mTOR pathway, and it can activate autophagy, and all of these would be longevity-based benefits. If you're going to fast for longevity, then it goes without saying, although I'm going to say it anyways, that the stricter you fast, the more you're going to activate many of these mechanisms.
On the other hand, if your goal for fasting is simply fat loss or let's say aligning your body to the circadian rhythm of wherever you happen to be in the world, it doesn't have to be as strict. It doesn't have to be like a strict water fast or completely absent of calories, like we know for example that just a 12 to 16-hour intermittent fast or even a mild amount of calorie restriction can help with body composition. We know that waiting to eat until it's the actual mealtime in whatever time zone that you happen to be in, which often does require fasting and sometimes doesn't, can align your circadian rhythm properly. And we know that for autophagy and cellular cleanup, not eating any sources of calories including fish oil, MCT oil, any source of calories, can actually enhance autophagy.
So, I would say fasting purely for longevity does involve stricter fasting, more frequent fasting, longer fasting. But if you're just simply trying to lose weight or to align your circadian rhythm, sometimes it just takes some alterations in the number of calories that you're eating or the time at what you're eating. And so, I personally try to strike a sweet spot. I fast for 12 to 16 hours every single day. I try to fast for about 24 hours, one to two times a month. That's like a Saturday dinner to a Sunday dinner. And then I do what's basically a version of what's called a fasting mimicking diet or an FMD four times a year, where I go for five days eating about 40% of the number of calories that I would normally take in. That's how I throw together my fast.
So, ultimately, if you're fasting for pure longevity, then I would encourage you to, during your fast, to really keep them strict and only have coffee or only have tea or only have water, absence of calories, avoid any supplements that contain calories. This should include fish oil, this should include amino acids, this should include pretty much anything that has calories. Even ketones have calories. You just stay away from all that. But if you're simply fasting to feel good and decrease some body fat and sleep better, then you don't have to be quite as strict. In my opinion, doing things like having a little bit of fat in the coffee in the morning to allow you to be able to go until lunch with good energy levels or taking amino acids before a fasted workout to maintain muscle levels, in my opinion, the speed bump for autophagy is very, very slight in those situations and the pros outweigh the cons. So, there we have it.
Next up, “Does coffee hurt or harm your fast?” Black coffee can enhance fatty acid mobilization from adipose tissue. It can enhance cognitive alertness. It can enhance metabolism. And if you're using like a French press and not a paper filter, a lot of the cholesterols in the coffee can get transported into the blood-brain barrier more easily. And so, coffee, without actual calories in it, no butter, no MCT oil, no coconut oil, no superfood creamers, nothing like that in the coffee, that's honestly going to assist the fast, not harm the fast.
There are some researchers like Dr. Satchin Panda who hypothesized that the taste of anything, including coffee, can cause this release of incretin hormones or other digestive hormones from the digestive tract that may either make you hungry or may disrupt some of the circadian rhythm benefits of fasting, or may decrease even potentially some of the autophagy benefits of fasting, but I've never seen research that shows that to be the case. And I think that in most cases, coffee, tea, sparkling water or even non-calorie sources of sweeteners like stevia, for example, in water or in your beverages, is just fine and does not hurt or harm your fast.
Hey, a quick interruption on today's podcast. I want to tell you, since we're talking about a spiritual discipline–I consider fasting to be a spiritual discipline along with meditation, prayer, silence, solitude, hiking in the wilderness in a toga, wearing sandals, sporting a beard. No, I'm just kidding. Well, I guess that's kind of a spiritual discipline. But gratitude, gratitude is a spiritual discipline. And in addition to practicing fasting regularly, I have a gratitude practice. I wake up every morning and I write down one thing I'm grateful for, and one person who I can help or pray for or serve that day, and one truth that I've discovered in my reading, because I start off every day reading something devotional or scriptural or spiritual, and it's transformed my life.
The power of gratitude, the science of gratitude for increasing lifespan and decreasing blood pressure and lowering cortisol, it's flabbergasting to use a very big, silly word. Anyways though, so I decided to take the exact gratitude practice that me and my kids and my wife do every day and make it available for you in a wonderful little heart bound journal that you can get over at christiangratitude.com. My mom and I picked out a bunch of really cool, inspirational Bible verses at the top of each page to inspire you each day. Even if you don't have time to read something devotional, you can just read that as you're reading for the day and it strikes your heart and it's special and inspiring. Dude, it's an amazing way to start your day. You don't have to be a Christian to use it, and it's still going to enrich your life tremendously. So, if you want to get one of those journals, just go to christiangratitude.com. That's christiangratitude.com. Alright. Thanks for listening.
Okay. Next up is, “I don't sleep well when I fast.” Man, that is common. Carbohydrates, particularly, we need at night. And this is why I tend to save most of my carbohydrates for the evening, not on days where I'm strictly fasting but on days where I am eating. I have more carbohydrates like sweet potatoes, tubers, yams, beets, parsnips, carrots, things like that with dinner, even a little red wine or dark chocolate because they can assist with sleep, because you get a serotonin release and a subsequent melatonin release, and you're not awake, and you get this slow bleed of energy while you sleep, and it simply enhances sleep.
And as soon as you start to fast, a lot of times you lay awake at night chewing on the inside your cheeks thinking about food. Sometimes it's because your carbohydrate deprived, low serotonin, low melatonin, sometimes it's because you're hungry. Sometimes it's because your nervous system is stuck in fight-or-flight mode, sometimes it's because you just can get by unless sleep when you're fasting, which actually is indeed the case. You can get behind less sleeping or fasting, so you may need less overall. You'll find sometimes that you wake up earlier when you're fasting and get through the day just fine.
But ultimately, I'm a fan of anything that can shut down the sympathetic nervous system for getting to sleep while you're fasting. Some of my favorites would be CBD. Most research on CBD shows that you need pretty hefty amounts to be able to enhance sleep. We're talking like 100 to 300 milligrams, considering the serving size in many CBD bottles. It's like 10 or less. That requires you to almost overdose on the CBD. But CBD can be very effective. There's a supplement that I use called Sleep Remedy made by Dr. Kirk Parsley that I really like. It has GABA in it, which is an inhibitory neurotransmitter.
A few other things that are used traditionally to shut down the nervous system or to calm the nervous system during sleep and to assist with sleep, and that I've found to be helpful in a fasted state for sleep, would be valerian and passion flower. Both of which can increase the GABA production. There is a compound called Kava or Kava Kava, which can also be helpful, as well as Chinese skullcap. There's a lot of different ways that you can do this but some of my favorites are the passion flower, the valerian, the kava kava, and the Chinese skullcap but what I personally do, because I get asked this question a lot, is I do two servings of sleep remedy and about 100 milligrams of CBD and I'm good. And that helps to cull my appetite when I'm fasting.
If you're doing daily 12 to 16-hour intermittent fast and this isn't a longer five-day fast, just make sure you're having enough carbs when you do have like an evening meal, for example, and that can definitely assist with sleep as well. And finally, don't underestimate the importance of breath work and meditation. A little breath work, a little meditation prior to sleep, just sitting, breathing, being mindful. I have whole articles I've written on breath work that'll include in the shownotes if you go to BenGreenfieldFitness.com/fastingQA.
But ultimately, yeah, the sleep component that's common but I'll also understand that you can get by on less sleep when you are fasting. And then finally, the only other thing I'd throw in there is that fasting can increase cortisol, and that's just like a counter-regulatory hormone that's meant to increase glucose in the blood while you're fasting. If your cortisol levels are elevated, there's some evidence to that supplement called phosphatidylserine. About 500/600 milligrams of phosphatidylserine may lower cortisol levels a little bit. And so, that would be another one you could throw into the mix if you just feel like you're amped up when fasting and lying awake in bed.
Okay. Let's move on to the next question, which is actually a really good one. “What is the hormonal effect of fasting on males and what is the hormonal effect of fasting on females?” Now, this is important because there is the concept of course of intermittent fasting, and I have found in my own coaching and consulting that I do with females that most of the lean and active females I work with tend to respond from a hormonal standpoint in terms of hormones like DHEA and progesterone and estrogen unfavorably to longer 16-hour intermittent fasts or extended fasts in general. Whereas, they do well operating closer to a 12-hour fast like stop stuffing food into your gaping maw at 8:00 p.m. and then you can eat again at 8:00 a.m.
Whereas males do not seem to have that issue, and indeed, in the exercise and fasting, which is a whole different episode that I released a couple of weeks ago, but in that exercise and fasting episode, I did comment on how even in a workout scenario men seem to do best fasting before workout and then eating afterwards. And women seem to do better with eating before a workout, and then fasting afterwards, meaning, not dropping like the hex bar at the gym and rushing off to Jamba Juice but maybe waiting a couple hours until their first real meal.
Then this may sound unfair but men, even though they do better with that first scenario, do okay with both. I personally do both in many cases. I wake up in the morning in a fasted state. I do 20 to 30 minutes of exercise most mornings. I do a little bit of a cold shower. I get some work done. And finally, at some point in that 12 to 16-hour window, I eat. And then I typically lift weights, or do high-intensity interval training, or play a sport later on in the afternoon or the early evening, like tennis or jujitsu. And then I also wait a couple of hours after my work out to eat. So, I kind of get two fasts in like a post-workout fast, if you want to call that a fast, and then also an intermittent fast. And guys do well with that, whereas women seem to do best with shorter intermittent fast, and then actually eating especially after a workout.
Now, fasting has an effect on a variety of hormones. We know that it affects the hormone insulin, and this is quite obvious. Everything from alternate day fasting to long duration fast to fasts, even as short as 24 hours, seem to shift the body into an impressive state of ketosis with lowering of blood glucose and a remarkable increase in insulin sensitivity. So, we know insulin responds favorably to fasting.
Growth hormone. So, over a five-day fasting period in one study, growth hormone secretion more than doubled. This means that if you are fasting and you simultaneously load the muscles while fasting, there was another study at University of California that showed this on a very low-calorie diet similar to a fasting mimicking diet, you maintain muscle. So, it's a very good signal. Lifting weights during a fast is to make sure that your body maintains that anabolic trigger and considering the fact that growth hormone can more than double during an extended fast. This means that once you've finished the fast, you're really positioned to be in a very good scenario to launch into a more muscle building or muscle gain program if that's something that you decide you want to do.
The interesting thing is that growth hormone also seems to go up even when you fast after exercise for one to two hours, like I mentioned earlier, without eating right after the workout. So, growth hormone responds favorably. In addition to that, it's not really a hormone as much as a catecholamine, but noradrenaline increases. And this is, of course, one of the reasons potentially that you actually don't sleep as well when on a relatively strict fast. But 48 hours of fasting has been shown to increase metabolic rate by nearly 4%, and a big part of that, you'd think it downregulated your metabolic rate but it doesn't. And sure, a long-term fast, and especially fasting for more than four weeks, and this is one of the reasons the folks on The Biggest Loser seems to actually gain weight, rebound weight after extended weeks, significantly longer than four weeks of being in a fasted state or calorically restricted state without any significant refeeds, that can downregulate the metabolic rate, going for a long time fasting without refeeds. But short-term fasts, even four to five days, seems to significantly increase metabolic rate, increase growth hormone, improve insulin sensitivity. There's a variety of effects.
I'm sometimes asked about testosterone. The boost in testosterone that occurs during fasting, I haven't seen exact percentages on. I know that it goes up. And again, I would highly recommend that you read Dr. Jason Fung's Ultimate Guide to Fasting to take an even deeper dive into hormones. But if it simulates what the response to growth hormone is, that too would be impressive.
Finally, I will also, in the shownotes for this episode over at BenGreenfieldFitness.com/fastingQA, link to a podcast episode in which I talked about another hormone called kisspeptin, produced dominantly by females that also dictates that females can respond more deleteriously to lengthy and frequent fasts compared to men. It's a highly politically charged discussion to hypothesize as to the reasons why such as men going out and hunting and gathering while women stayed at home preparing food and taking care of babies, but that also is the way that humans have operated largely up until recently.
And so, this could be a built-in evolutionary mechanism by women to maintain body fat percentages for childbearing, to stay at home, to take care of things in the home front while men adopted more robust fasting mechanisms by being warriors or hunters or gatherers or things along those lines. So, I know that's a difficult pill to swallow for a hard-charging, high achieving female who likes to fast but it may be that you're not yet at least genetically hardwired to do as well with it compared to males. So, it is interesting. I realized it's painting with a broad brush and that is a politically charged statement, but it does appear to be what science is at least showing at this point in human progression.
So, the next question is, “Does fasting slow down your metabolism?” Well, I guess I just answered that question about intermittent fasting and starvation mode or fasting in general and starvation mode. Just a quick clarification, the starvation mode, it's also known as adaptive thermogenesis. When you start losing lots of weight, your body tries to conserve its energy stores by reducing the number of calories that you burn by downregulating thyroid activity and cellular metabolism.
However, like I mentioned, that will occur after four weeks of relatively strict fasting with no refeeds, no extra carbohydrates thrown in at night every now and again if you're on a strict ketogenic diet, no days where you're eating at least as many calories as your body needs to sustain a normal metabolic rate may be on a weekend. This is why I'm a big fan of intermittent fasting with nightly carbohydrate refeeds for active people and for people who are doing like a 24-hour fast, which many of my clients do like a Saturday dinner to Sunday dinner fast. Having that Sunday dinner and/or that Saturday dinner would be pretty hefty, right?
So, remember, a lot of the magic of fasting comes from the time spent between meals, not necessarily the strict calorie restriction. A few things that have been shown though to help keep the metabolism elevated during a fasting scenario, one is protein intake, either amino acids or protein or some version of meat or fish or eggs included in a fasting scenario. What I mean by that is let's say you're doing an alternate day fast or an intermittent fast or a fasting mimicking diet or any variation of a fast, you're couching protein into that scenario, somehow. So, don't fast and then also just eat a very low protein plant-based diet unless, for example, you're trying to manage cancer or something along those lines. And then that's again an entirely different debate but if I ever had cancer, I would definitely be going on a protein-restricted, no red meat, no dairy type of diet based on a lot of —
There are good parts of that book, The China Study, and that is one good part as we know that high protein intake, especially from animal-based products in the presence of carcinogenicity or a tumor can indeed increase the growth of the tumor. So, that's why. Like I would do a full-on ketogenic plant-rich diet if I were to ever get cancer. You can lift weights. That will keep the metabolic rate elevated. And you can, of course, do some of those refeeds that I mentioned.
So, another question that I got was, “What other things can you do to enhance the benefits of a fast?” I thought this was a pretty interesting question, and I can tell you that if your goal is cellular autophagy, then there are a whole lot of things that have been proven to increase autophagy. I'll get into a few of them here. So, first of all, there are certain compounds that can increase cellular autophagy. I'm a fan of berberine. I'm a fan of bitter melon extract. Another similar one would be rock lotus extract. I've talked about that one before.
Any of these, like some of those are components, like bitter melon extract and rock lotus. In particular, those are components of Kion Lean. I take Kion Lean every day but you can literally take that three times a day during an intermittent fast to increase cellular autophagy even more. Just know that it manages blood sugar so well that it could result in hypoglycemia if you combine it with a lot of exercise. So, just kind of be wary of that and stick to largely aerobic exercise; yoga, sauna, swimming, et cetera, if you're going to take something like a supplement that would lower your blood sugar to increase autophagy during a fast.
A few other things that seem to be able to increase autophagy somewhat would be something I just mentioned, regular sauna session. Cold thermogenesis is another one, like doing a daily cold soak. I have one fun one that I have a lot of my clients do is they'll do a three by three, meaning–and then this is a little bit more intensive, but they'll do three minutes of a cold soak, like literally filling up the bathtub with ice-cold soak, like full-on cold soak. Three minutes of a Wim Hof style breathing or box breathing or some type of breath work to consciously control their response to cold, and then they go back into the cold for three. Back to breathing for three, back to cold for three, back to breathing for three. And if they're a person who gets cold very easily, I'll even turn it into a full-on workout and we'll toss some Airdyne or burpees in there where you have three minutes of actual exercise in between the breath work and the cold.
So, either way, that can also be quite potent for autophagy. Those are a few. The main things that come to mind would be sauna, cold thermogenesis, calorie restriction, the medics like berberine, like bitter melon extract, like rock lotus. And I suppose if you were looking at wanting to enhance the gut cleansing benefits of a fast, and four times a year, I do kind of like an Ayurvedic cleanse. And if you'd go to my podcast shownotes for this episode, I will link to a show that I did on liver cleanses. I actually do coffee enemas to basically increase the bile release by the gallbladder and get a little bit of an increase in phase 2 detoxification of the liver, and generally, just clean things out. Make it clean as a whistle. Plus, you can drink your coffee through both ends during your fast because we've already established the fact that coffee does not break a fast.
Similarly, another question that I get is, “What type of training is best well fasting and what type of training should be avoided?” So, anything that rapidly depletes glycogen levels and carbohydrate levels or that, by definition, increases your reliance upon carbohydrate during exercise is something that's going to be pretty dang uncomfortable on a fasted state and potentially drain you and also leave you unable to perform very well a workout like that, for example, in a gym or elsewhere. What do I mean by that?
This would be relatively intense exercise that is comprised of high rep, low weight weightlifting, or intervals that are pretty anaerobic and intense that are in that two to five-minute length of time, like Tabata sets, like high-intensity interval, training intervals that are two to five minutes in length. And the reason for that is you're just rapidly burning through carbohydrate versus weightlifting with high weight and low rep like a 5×5 deadlift squat, chest press, shoulder press, pull routine, or a Wendler 5/3/1 protocol, or a protocol like a super slow training protocol, something more reminiscent of powerlifting or Olympic lifting versus bodybuilding, right?
Bodybuilding is just designed to drain glycogen levels, whereas lifting heavy weights for brief spurts is fine, as is power, meaning like short bursts like 10-second bursts on a bicycle or even really up to two minutes in length because you got creatine to rely upon. You're not dipping into glycogen. That's significantly up to the two-minute mark. So, shorter bursts of high-intensity interval training, high weight, low rep weight training, and then anything passive anaerobic which relies primarily upon fatty acids in ketone.
So, any aerobic exercise at a conversational pace; walking, swimming, cycling, yoga, and even just passive exercise in a sauna or doing something like cold thermogenesis like I mentioned earlier or breathwork. Any of that works very well in a fasted state, and those types of things should allow you to move and boogie just fine for a long period of time while fasting. Remember, humans could go out for food, looking for food just fine in a fasted state for thousands and thousands of years. And there's no rule that fasting means you have to lay on the couch watching Netflix, as the overused analogy goes.
Okay. Next question. “How should you prepare for and break an extended fast?” The idea is that you'll generally have a little bit of a downregulation of digestive enzymes and some hormones called incretin hormones during a fast. And this means that when finishing a fast, you will be less equipped to be able to digest complex meals. Now, this is all said in the context of a longer fast. We're talking about like a three to five-day fast. You do not need to make any significant modifications to say your late breakfast or your lunch if you're doing something like an intermittent daily fast.
But for a longer fast, you should definitely plan on going low and slow when you're reintroducing foods, and basically, planning on spending a little bit more time eating, chewing, being in a very parasympathetic state when you eat, using bitters and herbs and spices like cumin and coriander and fennel and ginger and turmeric to allow you to be able to digest the food more easily, considering the use of supplements like Thorne Bio-Gest or Quicksilver Scientific's Bitters No.9 to allow you to be able to digest food a little bit more easily.
And then using the power of fire, and that would mean heat to do things like soft cook veggies or eat things that have been slow fermented or soaked or sprouted which pre-digests food. Considering the use of things like coconut creams and avocados and olive oils and grass-fed, grass-finished cottage cheeses or kefirs or ghee or even like raw milk, simple to digest fish, eggs to a certain extent, and no large amount of very complex, difficult to digest foods like large ribeye steak or a meal heavily laden with cooked fats and oils, and especially like red meats or things that you got to chew for long periods of time.
I mean frankly, what I've just described is a pretty decent diet to follow, like 80% of the time anyways if you have any gut issues whatsoever. But that would be how you'd break a fast. And then entering into a fast, I highly recommend the strategy, for example, used by my friend, Peter Attia. He calls it his “Nothingburger,” meaning that he will enter into a state of ketosis, meaning, shift to a carbohydrate-restricted or very low carbohydrate diet leading into a fast. And then also after the fast, ease his way out of the fast with again, switching back into a lower carbohydrate kind of ketogenic diet approach. He calls that again the nothing burger. And I really like that approach as well because by going into ketosis before the fast, you accelerate your ability during the fast to be able to enter into cellular autophagy and a lot of the benefits of a fast more easily, and it just allows you to keep your appetite satiated more easily during that fast. So, that's the way that I would do it.
“Is it okay to fast while breastfeeding or pregnant?” Well, this is an interesting question. When you look at cultures who have religious fasts frequently or at program times throughout the year, like the Orthodox Church, or the Roman Catholic Church, or the Muslims, or the Jews, or anyone observing a specific religious practice of fasting. Well, Jewish law actually exempts fasting for anyone whose health might be even slightly harmed by, and that includes pregnant and nursing women. And so, the pregnant and nursing women in Jewish religion are exempt from fasting. In Muslim cultures, women who are pregnant or breastfeeding can be exempt from fasting if they feel their health or their baby's health would be negatively affected by fasting. I'm not saying it is but I'm saying that these religions all have exemptions.
Roman Catholics, mothers who are pregnant or breastfeeding are excused from fast or abstinence, and they say, “According to need for meat and nourishment.” Latter-Day Saints, on their website, they say, “Nursing mothers may do well to skip fasting.” The Baha'i Faith exempts from fasting people who are ill, elderly, even pregnant, nursing, menstruating, or engaged in heavy labor. The Orthodox Christian Church has always exempted small children, the sick, the very old, and pregnant and nursing mothers from strict fasting.
Now, I realize this might sound like chronological or religious snobbery to say that, “Well, if all these religions say that these people are exempt, maybe they figured something out at some point that we don't know.” But then if you look at the studies on fasting and breastfeeding, they found a number of biochemical changes in the milk, including a drop in amino acids and some beneficial proteins in response to fasting. They have done other studies that have not found that the children grew any differently, but they have again found in other studies low levels of zinc and magnesium and potassium and other nutrients in breast milk, particularly.
I personally think that for pregnant and breastfeeding women, maybe an intermittent fast would be okay here and there. But ultimately, if I were ever pregnant, actually all the women who I advise when they're pregnant, they're eating like a very Weston A. Price diet and winding up having these big, beautiful, symmetrical, wonderfully, healthy babies who grow up with big heads of hair and a full set of teeth. And these women, I have them eating lard and ghee and a raw milk and cheese and kefir and yogurt and organ meats and bone broth and ferments. There's amazing assortment of food just eating and eating and eating, sending the body this message that it's not a time in famine, it's time to make this amazingly fat baby. By the way, that's different than sugar. You don't want to be with pre-diabetes or insulin insensitivity or insulin resistance, but I say the pros are outweighed by the cons when it comes to fasting for breastfeeding or for nursing.
Okay. “Does your ability to absorb food and supplements increase after a fast?” Well, this is something I actually discovered while bodybuilding and while racing an Ironman triathlon. There's an enzyme called glycogen synthase that's responsible for taking carbohydrates and sucking them away into muscle, and to liver to a certain extent, I believe. And by restricting carbohydrates for certain periods of time a.k.a. kind of a carbohydrate fast, the levels of glycogen synthase go up so that when you do eat carbs, they're more likely to wind up in the muscles, in the liver. And this would had been a strategy like before a race, like restricting carbohydrates and doing a whole bunch of carbs a couple days before the race really amp up the body full of carbs. They're very similar with bodybuilding to fill up the muscles with carbs.
But in the case of fasting, yeah, you'd see an upregulation of glycogen synthase. So, that's one that we know response to fasting. Another thing that's interesting with fasting is other enzymes–actually, if there's ever a perfect time to do mega doses of enzymes for maximum benefit, it would be during times of fasting because these digestive enzymes can–rather than being used to digest food, go straight to accumulated scar tissue and broken ligaments and muscle and skin fibers. There's one supplement called Masszymes, and I'll link to this one in the shownotes. I've done a podcast with them too before. That is actually perfect for this. Like taking 6 to 12 Masszymes a day while you're on a fasted state can do a wonderful job at healing the body. And I'll often take enzymes that are designed to digest food and instead use those during a fast to amp up the repair and recovery benefits of a fast.
Another really good one to do during this time would be Kion Flex, because Kion Flex not only has proteolytic enzymes in it that repair muscle tissue, but a lot of these different enzymes that again, traditionally would be used to digest food but can be used to repair muscle during a fast. So, after the fast, if you've ease yourself into it, based on what occurs with glycogen synthase, it's likely that many of these other enzymes responsible for upregulating digestive enzymes, especially if you ease yourself back into eating, are affected positively by a fast. I was unable to find a lot of data on which enzymes but I know it's a fact for glycogen synthase because that's similar to a lot of these other digestive enzymes, likely for the others too. And again, just speaking of enzymes, it can be kind of a hack to throw in enzymes to a fast. And I'll link to the Flex and into the Masszymes in the shownotes over at BenGreenfieldFitness.com/fastingQA.
Now, as part of all the questions I got about fasting, a large number of them–I think because people are so aware that I am a huge fan of amino acids–I use amino acids regularly in my training. I use them to go into a fasted workout but stay in an anabolic state by taking as little as 5 and as many as 20 amino acids to maintain high blood levels of amino acids during a workout. I do not use branched-chain amino acids, which just contain three amino acids; leucine, isoleucine and valine. I instead consume a whole spectrum of amino acids that are very good for anabolism, for gut repair, for joint repair, very similarly like collagen.
So, I use essential amino acids, and I use that every day. That's a supplement that's just like rocket fuel. It's like steroids. I use essential amino acids every day. And I also will use them if I am fasting and I want to maintain muscle or I'm working out hard while I'm fasting because sometimes I want to have my cake and eat it too. I want to do some of those harder workouts while I'm in a fasted state. Sometimes because of all the adrenaline release in the cortisol, I have higher levels of energy anyways, and essential amino acids just get me through that like gangbusters.
Now, do they break a fast? Well, they have a mild amount of calories. They're non-insulinogenic, meaning they're going to spike blood sugar. They're not going to reduce the glycemic impact of fasting. Branched-chain amino acids will; essential amino acids don't. But they do, if your pure purpose of a fast is cellular autophagy, keep the body catabolic clean it up, et cetera. Then I wouldn't use any source of calories including amino acids or any source of anabolic stimulant at all during a fast. However, if you just want a fast for the gut cleanup, for their circadian rhythm benefits, for the glucose stabilizing effects, for the spiritual effects and you still are wanting to work out and exercise, essential amino acids fit beautifully, in my opinion, into a fast. I think any active person who fasts should definitely include them in their arsenal.
The trick, if you're going to use them, is to preferably time them around the time you're going to be exercising anyway so those amino acids are used very anabolically. And I didn't mention this in my reply to sleep. You can use them prior to sleep too to stabilize sleep and to give you a slow bleed of anabolic muscle repairing or muscle building energy during sleep. So, for example, a very good stack like a fasting supplement stack would be something like essential amino acids, some kind of enzyme source like Kion Flex. And then if you wanted to throw ketones in the mix, you could even though those have even more calories. But for a workout, you could throw ketones in. And any of that, that would be, along with coffee, like a very good way to fast, like do coffee, Kion Flex, Kion Aminos. Maybe I'll put together a little fasting package for you guys over at Kion for those of you who want to support the fast in that way.
Now, in fact, one study that I found showed a significant muscle preserving effect of essential amino acid supplements when ingested especially during training in a fasted or ketotic state. And that study includes decrease indicators of muscle damage and decreased inflammation. So, that means if you pop essential amino acids, even if you didn't need anything, you won't cannibalize as much muscle during a fasted workout session or a long intermittent fast or a bout of ketosis or a freaking marathon or Ironman triathlon or anything like that. So, I just think they fit beautifully into this fasted scenario. You just want to make sure you've got all nine, preferably, you got phenylalanine, valine, threonine, tryptophan, isoleucine, thiamine, histidine, arginine, leucine and lysine. You want all those amino acids in the correct balance in the amino acids that you use.
Yeah, I'm a huge fan. Stack something like Kion Aminos along with Kion Flex and that's perfect for fasting. By the way, just to complete aside on amino acids, and we do have a brand-new berry flavor going live on Kion very soon, I think around the time of this podcast, it tastes like crack cocaine–actually, I don't know what crack cocaine tastes like but it tastes really good.
I did get two questions about gastrointestinal effects of amino acids and dry mouth during amino acids. Now, dry mouth is something some people get when they use like an amino acids powder. One of the reasons for that can often be issues with digestive enzymes or salivary production. There are certain herbs that can stimulate salivary production in people who have difficulty producing enough saliva, who get dry mouth frequently.
So, this is a complete aside but I wanted to note, one that I grow at my house is called Spilanthes. It's a popular herb used to clean the mouth. It's called the Electric Berry. It tastes like a party in your mouth when you pop one. They're incredibly easy to grow. I just bought the seeds on Amazon. I grow them at a little pot at home. That's amazing for dry–you pop one of those berries before a meal and your mouth just fills with saliva. So, those are good. You can have those around like me. I just have a little pot around my office and I think there's at any point like 30 little berries I can just grab. They have literally no sugar. I mean, they're almost more like an herb than a berry.
Ginger also is a very good one. Chewing on a little root of ginger or a little chunk of ginger can increase salivary production, as can just a bit of cayenne applied on the tip of the tongue or on the inner lips or on the inside of the mouth. Just a very small amount can also increase salivary production. So, it was just a couple of tips for you for dry mouth. I know that sounds completely random but it was a question that I got.
And then the other question that I get with amino acids is whether you get adverse gastrointestinal effects with them. Now, that's not typical but there are some people who particularly do not respond quite as well in terms of nitric oxide production in the small intestine in response to certain forms of amino acids, and with a lot of those people that can be what's called a histamine sensitivity, a histamine sensitivity.
Now, there are things you can take that lower histamine, like my friend Dr. Ben Lynch has been on the podcast before. I actually have this supplement. I'll take it sometimes if I'm going to have more than one glass of wine, for example, or a hefty amount of fermented foods like my wife's lovely sauerkraut and kimchi. They make one called Histamine Block and another one called Histamine X. Histamine X is a specific probiotic formula that's low in histamine producing bacteria. And then Histamine Block is one that actually can block the production of histamines.
If you tend to get gastrointestinal symptoms upon consumption of anything that has high amounts of amino acids in it, particularly arginine, citrulline are two that can tend to cause that, you may be someone who's histamine sensitive and who just needs to throw a few extra histamine supplements into the mix. I realized for the past 15 minutes, I've mentioned a lot of different supplements but it's part of what I do. It's part of my job. My master's degree is in Physiology with an emphasis in human nutrition and pharmaceuticals. And so, I'm okay and open to the idea of using better living through science or nature's ingredients, what have you, to make life better.
Anyways, so let's see. Yeah, those are the main questions really that I wanted to go over regarding aminos and fasting in general. Geez, those were all the questions. I'm just realizing. Yeah, those are all the questions that I got. And I probably generated like a billion more questions during this recording. So, here's the deal. I'll put up the shownotes over at BenGreenfieldFitness.com/fastingQA. And then if you wind up having follow-up questions, just leave them over there. I'll put links to everything I talked about. I'll get some good links up for Kion as well over there for the Kion Aminos or the Kion Flex, as well as some of these other things like Histamine Block and Histamine X.
And then, yeah, if you have questions, ask them. Sometimes these solosodes are awkward to end because I'm like, “What do I say?” Leave the podcast a review in iTunes, I guess. Oh, one thing. There is a free fasting guide that I made that you can just download for free. That one is at getkion.com/fast. That's getkion.com/fast and it is just chuck-full of a whole bunch of guides for alternate day fasting or fasting mimicking diet or elemental diet or liquid diet, just everything you need to know about fasting in general and how to pull it off, assuming this Q&A didn't just answer all your questions. So, there you have it. Thanks for listening. I hope this was helpful. I hope you like these solosodes. I'm Ben Greenfield over and out, like a trucker would say.
[0:57:13] End of Podcast
Hey, that's it. Thanks for listening to the show. You can grab all the shownotes to resources, pretty much everything that I mentioned over at BenGreenfieldFitness.com, where there are plenty of other goodies from yours truly, including the very helpful “Ben Recommends” page. Now, one last thing, please know that all the links, all the promo codes, pretty much every resource that I mentioned to you during each episode, really helps to generate income for the podcast and it kind of helps to float this thing and enables me to keep spending the time to bring you the content every week. So, be sure to use the links, use the promo codes, use all of those goodies too. Alright. Thanks for listening.
The recent Kion 5 Day Fasting Challenge has now come to a close – and we had over 10,000 people participate (that's a whole lot of food that wasn't eaten).
During the fast, I received plenty of questions about fasting, such as:
- Does coffee hurt or harm your fast?
- What can I do to improve my sleep during – and after – a fast?
- What is the hormonal effect of fasting on males? And what about for women?
- What is the best kind of fasting if your goal is body composition (fat loss, muscle gain/maintenance)?
- Does fasting – especially 3-5 day extended fasts – slow down your metabolism?
- What type of training is best while fasting, and what type of training should be avoided?
- What other things can you do to enhance the benefits of a fast? (e.g. cryotherapy, enemas, etc.)
- How should you prepare for – and break – an extended fast?
- Is it OK to fast while breastfeeding or pregnant?
- Does your ability to absorb food and supplements increase after a fast?
- What are your thoughts on EAAs while fasting? Do they break a fast? And what about BCAAs?
- And many more!
During this Fasting Q&A Solosode, you'll discover…
-How does fasting for longevity differ from fasting for things like fat loss or circadian rhythm…7:45
- Decreasing calorie intake 20-40% is the most optimal way to regulate aging and increase life span
- Inhibit mTOR pathway, stimulate autophagy, induce ketogenesis
- Autophagy: “self-eating” – not to be confused with apoptosis, which is cell death
- Autophagosomes to lysosomes “spring cleaning in your cells”
- Eating shuts down autophagy; fasting increases autophagy
- mTOR: mammalian target of rapamycin
- Energy enzyme
- ATP becomes ADP
- Every time you eat, you activate mTOR and suppress autophagy
- Ketosis: using fat as the primary source of fuel
- Less oxidative stress; slows the aging process
- My personal protocol:
- 12-16 hour intermittent fast daily
- 24 hour fast (dinner to dinner) twice a month
- Fasting mimicking diet (FMD) 4x/year
-Whether coffee helps or harms your fast…16:50
- Black coffeecan enhance fatty acid mobilization from adipose tissue, alertness, metabolism.
- Coffeewithout any calories added (coconut oil, butter, etc.) will help the fast
-How fasting can affect your sleep…20:05
- Carb intake at night (dinner time) assists with sleep
- Shut down the sympathetic nervous system to get to sleep while fasting
- You can get by on less sleep when you're fasting
- Don't forget the efficacy of breath work and meditation
-Hormonal effects of fasting in men vs. women…23:40
- Lean and fit females do better with shorter fasts (12 hours); men are more versatile
- Insulin, growth hormone, responds favorably to a fast
- Noradrenaline increases with fasting
- Level of testosterone increase while fasting is unknown
- Podcast on kisspeptin
-Whether fasting can slow down your metabolism…30:45
-Tips for enhancing the benefits of a fast…33:20
- Bitter Melon & Rock Lotus extract
- Kion Lean
- Sauna sessions
- Cold thermogenesis
- Podcast on liver cleanse
-The best types of training to engage in while fasting…36:25
- Anything that rapidly depletes glycogen or carb levels will have deleterious effects
- High weight, low reps; bodybuilding vs. weight lifting
- Walking, swimming, yoga; something you can do and have a conversation
-How to properly prepare for and break an extended fast…38:55
- When finished with a fast, you'll be less equipped to digest complex meals
- Go low and slow when reintroducing foods
- Soft cook veggies
- Avocados, grass feed cottage cheese, eggs
- No steaks; anything you need to chew for a long time
- Peter Attia's “nothing burger”
-Whether or not it's ok to fast while breastfeeding or pregnant…42:18
- Religions encourage women to refrain from fasting while pregnant or breastfeeding
- Biochemical changes in milk in response to fasting
- Think “feast” not “famine”
-How fasting affects your body's ability to absorb food and supplements…45:38
-Essential Amino Acids' effect on fasting…48:15
- Don't use them if your goal is cellular autophagy
- Can be very useful for resetting circadian rhythm, gut cleanup, spiritual benefits, etc.
- Can be a good mTOR activator
- Dry mouth, from amino acids:
- GI effects:
-And much more!
Resources from this episode:
–Kion Berry Aminos Building blocks for muscle recovery, reduced cravings, better cognition, immunity, and more*. Now in a DELICIOUS berry flavor!
–JOOVV After using the Joovv for close to 2 years, it's the only light therapy device I'd ever recommend. Give it a try: you won't be disappointed. Use my link when you order and get a FREE bonus gift!
–The Christian Gratitude Journal When you introduce conscious, mindful gratitude into your day, positivity will begin to pour into your life – along with all the other scientifically proven physical, mental and spiritual benefits that go along with it.
*These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure or prevent any disease.