A recorded interview between Dave Asprey and a host discussing fasting as a tool for longevity and metabolic health. Key practical claims: a Japanese study cited ~58-hour fasts linked to increased life expectancy; intermittent fasting (even 12-hour daily fasts) yields benefits; longer fasts (50–72 hours) are discussed as achievable with practice. Asprey emphasizes fasting's effects on insulin sensitivity, inflammation (linked to mitochondrial dysfunction), increased mental focus/flow via ketones and energy reallocation, and timing exercise at the end of a fast to improve results. He critiques oversimplified diet labels ("plant-based"/"animal-based") and highlights avoiding seed oils and toxic foods.
Questions this video answers
About 58 hours.
72 hours.
48% of people under age 40.
Chapters
One of the things that I found very interesting in the book was the study that, I guess the Japanese study that was done, that the 58, roughly 58 hour fast time frame actually increased life, life expectancy.
Even intermittent fasting can do that. But in the Japanese study it was 58 hours of fasting. I don't remember how commonly they were doing that. I think it was what, once every month or two if I remember. It wasn't that frequently. So 58 is a good number. But it comes down to you start getting benefits. If you do a 12 hour fast most days you are going to probably live longer. And if you don't live longer, you're going to have way less metabolic disease over time. That's not that hard to do. Literally early dinner, don't eat breakfast too early, you nailed it. That's very entry level. And what people find is once they start doing the intermittent fasts that I write about in fast, this way you kind of work your way up and then you realize, you know what, I, I only need to eat once a day on some days. And so you have like a lunch that's really big and then you're just, you're good. And dinner time comes around, you're like, man, I'm just really not, I'm not very hungry, I don't need to eat. And maybe it'd be pleasant to eat, but you're just not. And then you say, okay, I have some time, you know, maybe over a weekend. I'm just going to have dinner on Friday and I'm not going to eat until Monday. And all of a sudden, well, if you wait until dinner on Monday, you would have done a 72 hour fast. You have lunch on Monday, you, you just did a 50 something hour fast like the Japanese study. Most people though, when they do that the first time, if they've never done any fasting before, they're going to really feel awful. So work your way up to it. And I did, about two weeks ago, I did a 72 hour fast in the middle of a workweek. I did one of those days. I had six interviews on podcasts. You know, as a host and as an interviewer, like all of your brain is engaged. I'm showing up fully to be able to do that without worrying about food, without thinking about food, without just like, I'm in the flow, I'm in the zone. Fasting is meant to put you in the zone. And it's really cool because when you really think about it right now, the average person, 15% of your thoughts every day are about what's for lunch or what's for dinner, like what's for my next meal. When you're fasting and you've turned off your hunger properly, using the tools that I talk about in the book, you actually get 15% of your thoughts back. So instead of looking at you right now and going, tacos, I'm just looking at you.
So there's 15% bonus. And all the energy that would have been going to work digesting food so I could use it later, all that energy returns to my brain or to my repair systems because it's not breaking down food. And then food is a combination of three things. There's calories, which is another word for energy. Calories are not bad for you. You actually need them to function. And so there's calories, there's nutrients, vitamins and minerals and then there's stuff that's bad for you because plants don't want you to eat them. Right. So every food is the combination. Some amount of energy, some amount of good stuff and some amount of bad stuff. But most common literature, especially popular press nutrition, only talks about the good stuff. So you could literally be like, oh, here's a bowl of cyanide and I put a vitamin tablet in there and like, oh, that's a high nutrient density bowl. Because they don't count the negative stuff. Right. When you are fasting, whatever negative stuff you're getting doesn't get to detract from your energy. Your energy for digestion is now available for use. And you're not thinking about food. So this is the best day ever. And you get some ketones going. Ketones have more energy than carbs anyway. And your neurons are like, I'm in an exalted state. I can go into flow state. I can do stuff I couldn't do before. And right now, let's see, I had dinner at 5 o' clock last night and it's 11am today and I worked out this morning and I'll probably eat in a couple hours.
Yeah. And you're wide awake and we're having a good time. Yeah.
Right. There's no stress.
Yeah. It's funny thing, when I first began intermittent fasting, even though I'm a week on, a week off kind of guy, I'll get better. I'm working my way up. As you, as you, as you prescribed. One of the things that I do notice is a higher level of increased focus.
Yeah.
I also noticed that when I began fasting in general, I began cutting out all Carbs, which caused me to have the cold carb hangover scenario. And I also cut out all sugars. And I was able to go without sugars and stuff like that just in general for, gosh, probably two or three months. And if I had even the slightest taste, you know, a few months later of a sugar, the sugar itself was tweeter or sweeter. Yep, it's really surprised me until I got to know that term insulin resistance. Correct me if I'm wrong, but insulin resistance by itself detracts more from the body and harms the body, everything from obesity and other things than probably anything else, which is one of the things fasting directly offsets.
Insulin resistance is bad for you. It means your body has a hard time processing the primary fuel for the human body. And that means you have a metabolic weakness. And so that metabolic weakness is a precursor to diabetes, which is a precursor to all the diseases of aging. So you really don't want to be insulin resistant. And things like heavy exercise, high intensity interval training, things like fasting, things like sleeping well, all help with insulin resistance. Not eating toxic foods, not eating seed oils. These omega 6 oils present in especially restaurant foods because they're cheap, all of those things contribute to insulin resistance. But intermittent fasting is one of the easiest things you can do to improve that. And one of the other hacks that's in the book is you can time your exercise. So what you do ideally is you do an intermittent fast. At the end of the intermittent fast, you exercise. And exercise doesn't have to be crazy. You can do 10 minutes of air squats and some pushups. There you go. You could also go to the gym and lift real heavier. You could sprint or whatever. But I don't mean like a full crazy workout. Unless you want to do that. Then you eat. And the results you get are profound. Way better than if you ate and then worked out. And there's some really neat biology here. And what's happening is that we didn't understand the biology well enough to have an instruction manual for the human body that said, oh, here's how to do it to get the best results. So instead, like, I'm going to eat three bananas to go to the gym, so I have energy. How about this? Tell the body, if you can't make enough energy from burning fat at the gym, then deal with it anyway, and then lift. And it's funny because people are like, well, I'm not going to have a good workout. But a lot of people set their personal best because all the energy that was going into digestion is now going into lifting. Right. So you set a PR and you're like, that's weird. I set a PR on an empty stomach. Who would have thought, right? And then you can have the, you know, the pre workout or the post workout, or you can just eat a steak or some eggs or whatever it is you're going to eat. And maybe even have some carbs, because carbs can help you put on muscle after you work out. But that doesn't mean corn syrup and malt. Objection. And crap carbs because not all carbs are the same. And this is another really important thing that's a part of fasting. We love to make things simple. If you say fasting is good for you, fast all the time, you're not gonna like what happens to your life because it's only good for you in the right doses. And then we like to say things like a plant based diet is good for you. I'm like sarin, the nerve gas they used in the Tokyo Subway Tech. That's a plant based protein.
So what?
Yeah, sarin, the nerve gas, Right. So in fact, most plants, if you go out into your backyard and you don't have a garden, you have a garden, just pick a few leaves and eat them. And you'll probably end up in the hospital, if not at least in the bathroom. Right. Plant foods are not good for you, they're not bad for you. You have to know what plant food and how is prepared or it's a meaningless statement. A plant based diet, whatever. Now are animal based foods good for you? Well, spider venom doesn't seem like a very good animal based. So plant based, animal based protein.
You took my protein away from me.
Well, they're both garbage. Those words don't mean anything. So some plants make you hungry, some are very high in nutrients and low in toxins. Those are good ones. And some animal foods, like grass fed animals, are profoundly good for you and they're actually good for the planet. And other ones are bad for you and bad for the planet. And if you step into a slim gym or whatever, you go, well, that's keto. Sorry, it's going to cause inflammation. So you got to pay attention to that as a part of this as well.
I actually want to drill down on inflammation just for a few seconds.
Sure.
With you, I'll just say a personal. Just be honest with you and transparent about something. My beautiful wife, who is amazing. We have been married now. We just got celebrated our six year anniversary.
Yeah, I like her a lot.
Yeah.
I'm just. I'm just sounding like a jerk.
No, she's going to love you to death, man. Sure. She watches all the episodes as well. One of the things that has been important in our life is she has a high, high level of endometriosis. So she's had a full hysterectomy, has been through horrible surgery after horrible surgery after horrible surgery.
So much of her pain, her regular pain, comes from a higher level of inflammation on a regular basis. Yep. Talk to the audience about the importance of getting the inflammation down and how to do that, especially with fastest way, because I think it's vital to the conversation nowadays.
Oh, it is. So inflammation. When you peel away all the different things behind is one thing. It is mitochondrial dysfunction, your body's main thing. When you strip it all down. 30 pounds of air every day and X amount of food or other, other substrates that you're pulling out of your tissues. Right. If you do a great job of combining those things, all that comes out is electrons, energy to think, to feel, to act, to breathe, to do, to be.
48% of people under age 40 have early onset mitochondrial dysfunction. That means they suck at turning air and food into energy. They turn it into energy. And the part they don't turn into energy turns into inflammation. Hey there.
If you really enjoyed that snippet, you're really going to love the full interview right here. So make sure you check it out.
It's the easiest way to lose weight. It's the easiest way to become sensitive to insulin again. It's the easiest way to reduce your risk of depression, diabetes, of Alzheimer's, of cancer, of heart disease. And you can still eat whatever you eat today.
