The Truth About Fasting (Here’s What Actually Happens)

Fasting is one of the oldest and most proven health practices in human history. People have used it for thousands of years to improve physical health, sharpen the mind, and even deepen spiritual connection. And yet, even with all that history, fasting is still one of the most misunderstood things in health and fitness. And sure, if you do fasting the wrong way, it can backfire. But if you do it the right way, fasting can be one of the most powerful tools for your body, your brain, and even your spiritual life. So in this video, I'll break down for you the real benefits of fasting, the biggest misconceptions, and then at the end, I'll answer the top questions that I get all the time about fasting. A lot of people ask me about my own personal fasting practice. Now, fasting varies from person to person in terms of how they implement it in their own life. I have friends who often every single month will fast for 3 to 5 days. I know other people who Every year we'll fast for 7 days. Some people fast for 10 hours for every 24 hours, 12 hours for every 24 hours, 16 hours for every 24 hours. There's all sorts of different styles of fasting, but what I personally do is a 12 to 16-hour intermittent fast for every 24-hour cycle. That means that if I finish dinner at 8:00 PM, I'm not eating again until at least 8:00 AM. And if I get up and have a midnight snack, guess what? I'm not eating again until noon. Now, Now in addition to that, 1 to 2 times a month I do a 24-hour dinner time to dinner time fast. That means that after dinner on Saturday night, I don't eat again until dinner on Sunday. And the reason that I implement that is because when you fast for longer than 16 hours, that's where a lot of the cellular cleanup and longevity benefits start to kick in. Finally, 4 times a year or every quarter, I do a longer version of what's called a fasting mimicking diet, or FMD, where I go 3 to 5 days with reduced calorie and reduced protein intake. For me, this usually comes out to anywhere from 500 to 800 calories per day, less protein, and more of a focus on things like juices, bone broths, water, electrolytes, and multivitamins. That's what my own fasting protocol looks like. It will vary a lot from person to person, but I just want to give you a glimpse of what I practically do. So what are some of the benefits of fasting? Well, improved body composition is one. There's no surprises there. Fasting for 12 hours or more can help shift your body into greater amounts of fat utilization. This amount of fasting can also increase what's called human growth hormone, which interestingly can not only help you burn more fat, but also help you maintain muscle, which a lot of people are concerned about losing when they fast, which is really not as big an issue as a lot of people have been led to believe. So this growth hormone can help to preserve muscle while also simultaneously upregulating your burning of body fat, which when combined with consuming fewer calories can really improve body composition. Fasting can also help you to produce more energy. Now, when you're hungry, your body becomes more alert and more active. Perhaps this is some kind of built-in biological mechanism that would've made you more likely to be a successful hunter or gatherer when you didn't have access to food. Now, part of that alertness is due to the rise in something called adrenaline. This is basically your body's way of energizing you to help you go out and find food. Next up is appetite regulation. Fasting can help to regulate hunger and fullness hormones. Now, ghrelin is a hormone that makes you feel hungry. I remember this by thinking about ghrelin and the stomach growling. Leptin is a hormone that signals to you that you are full. Now, fasting can help to balance ghrelin and leptin in a way that improves appetite control, meaning that the more frequently you fast, the better job you start to do at balancing these hormones and quieting a lot of hunger signals. Next up is gut health. This is a big one for me and one of the reasons that I'm a huge fan of that 12 to 16 hour daily intermittent fast, because it gives my gut a break and it helps to protect my gut from stress. It can do the same thing for you, but it can also improve your gut bacterial diversity. That helps to make not only your gut more resilient, but your immune system stronger, which leads me into one of the next benefits of fasting, and that's overall immune system health. Fasting can actually help to support the immune system, and one of the ways that it does this is it clears out damaged cells, and it may also help the body to repair and regenerate tissue. There's also emerging research that fasting may also help to modulate some autoimmune conditions, which is also an important component of immune system health. Now, fasting can also support your brain health. You've already learned about adrenaline and the alertness that fasting can provide, but fasting can also help protect nerve cells through something called autophagy. It may also increase brain-derived neurotrophic factor, or BDNF, which sort of serves as like a Miracle-Gro for your brain, helping to grow new brain cells and new neural pathways. That can support memory, learning, and overall brain function, cognitive health, and focus. Fasting can also help to support your cardiovascular and your metabolic health. It can improve things like blood pressure, cholesterol balance, blood sugar management, or glucose up and down swings, insulin sensitivity, and triglycerides. Now, you've probably heard about fasting for longevity and disease prevention. This is because fasting helps to increase something that I've already mentioned a couple times in this video—autophagy, your body's natural cellular cleanup process. That means your cells clear out old and damaged material and replace those cells with new material. This is one of the reasons that fasting is linked to anti-aging, longevity, and better metabolic health. Fasting also builds self-control and discipline, which is perhaps why it's also linked to the elements of many religious or spiritual practices. Practicing restraint, choosing not to give in to hunger, right away can carry over into restraint in other areas of life. It can strengthen your ability to resist distractions and temptations. I also really like to fast if I have a very, very busy day where I want to focus on a lot of tasks. Not only can food noise be distracting, but it can also take away extra time from working on an important project to go off and need to eat a meal or prepare a meal. A little bit of rapid-fire FAQs here when it comes to fasting. First of all, I'm often asked if coffee breaks a fast. Think about it this way: Anything that contains an appreciable number of calories will break a fast. So black coffee does not break a fast. An orange mocha Frappuccino or an originally black coffee with a whole bunch of cream and sugar in it does break a fast. Now, coffee is actually an interesting one along with some teas because the caffeine in them can also help to support a fast. They can shift your body into a higher amount of beta oxidation or fat burning. It can also help with alertness and overall metabolic rate. Just don't add a bunch of butter or MCT oil or coconut oil or creamer or sugar or anything else to that morning beverage if you truly want to stay fasted. Now, other things that don't contain calories like black tea, sparkling water, non-calorie sweeteners like stevia or monk fruit would also be generally fine. But if it has calories, it breaks a fast. Now, for some people, fasting can make sleep harder, especially at first, because you're not used to going to bed hungry. Sometimes you can have low blood sugar. Sometimes you can be more wired from some of the adrenaline that fasting can create. Now, some people simply need less sleep when they're fasting because fasting actually helps your body with a lot of the cellular cleanup that would normally occur when you're sleeping. So if you normally sleep, let's say 7 to 8 hours a night, when you're fasting, you might be able to get away with 6.5 to 7.5 hours a night. But if you want to sleep better when you're fasting, I recommend engaging in practices that help to calm the nervous system. This can be breathwork such as a 4-count in, 7-count hold, 8-count out, some type of meditation to calm the nervous system prior to sleep. I also really like different apps that will play sounds that help to lull your body into a rest-like state. There are apps like NuCalm or SleepStream for this. And finally, things that vibrate, devices like the Apollo or the Sensei, can really help to lull your body into a relaxed state. You shouldn't have to hammer your body with supplements and pharmaceuticals in order to be able to sleep better when you're fasting. So another question I get is whether you can or should, uh, train when you're fasting, meaning like exercise, lifting weights, going on runs, etc. Now you can train while you're fasted, but some workouts typically feel better than others when you're fasted. So for example, if I'm going through a hefty period of days where I'm eating fewer calories and less protein, I will focus more on things like yoga, sauna, long walks, and other deep restorative activities that still involve movement but that don't beat up my body or require as much protein and calories, for example, for recovery compared to, say, heavy strength training or high-intensity interval training. Now, anything that burns through carbs super quickly, such as like a hard CrossFit workout or doing multiple cardio repeats or high-rep weightlifting, would be something that really wouldn't feel that great when you're fasting. And many people struggle with energy with those type of workouts in a fasted state, especially if they're fasting for longer periods of time. So Metcons, high rep lifting, Tabata sets, hard intervals— basic rule is that quick hard bursts and slow aerobic periods are fine, but those mid-length hard efforts that are very what are called glycolytic tend to suffer a little bit. Finally, for some people who are concerned about losing muscle, even though the growth hormone that you you produce during fasting is going to help keep that from occurring will wonder how they can get protein if they're fasting for long periods of time, or even just engaging in general calorie restriction for a long period of time. Uh, there is one tool called essential amino acids that can actually provide your body with 9 of the building blocks that it needs for things like neurotransmitters and muscle growth or muscle maintenance, but does not contain an appreciable amount calories and does not produce a very high what's called insulinogenic response when consumed. So for example, let's say you are going for 3 days at, uh, 700 calories per day. You still want to stay active and you still want to maintain muscle. You could, for example, take anywhere from 5 to 20 essential amino acids, and that would be in grams for each of those days. I'll often use essential amino acids when I travel and I'm not eating much or during periods of time where I'm fasting for a longer period of time, but I want to stay relatively anabolic. All right. So, if you haven't messed around with fasting much, I got a quick challenge for you this week. It may actually be harder than you think, but I want you to try this anyway. Try to go for the next 7 days giving your gut and your body a 12-hour break from eating for each of those 24-hour cycles. So, that means, again, if you finish dinner at 8:00 PM, don't eat again until 8:00 AM. That sounds theoretically easy, but that handful of dark chocolate covered almonds or that scoop of ice cream or those couple tablespoons of creamer in your coffee are all things that you would avoid during that time. Pull that off and then you can move on to some of the other fasting tips that I've given you in this video. So part of your reason for fasting includes getting lean or maybe getting some six-pack abs. Check out this core training video that I think will pair quite well with your newfound information on fasting. If you have questions, comments, feedback, Leave them right here. I'd love to hear what you think.