I wake up, I have green tea with my breakfast and that's my first caffeine in the day. And then I sip coffee while I'm riding in the morning. And that may be why I only write in the mornings, because I'm trying not to drink caffeine in the afternoon. So I guess I'm a slave to the substance.

Like many people, science writer Michael Pollan, who's my friend, gets through his days with the help of a morning cup of green tea, followed by a cup of coffee. But a while back, he decided to do something different, make a change to his routine.

Now, I've been drinking coffee since I was like ten. I got started really early, so I had not had a period without caffeine in a very long time. So I went through this withdrawal and wanted to see what it would be like.

Pollan was in the middle of writing a book about psychoactive substances, including caffeine, and that's why he decided to quit cold turkey for three months. What he really wanted to understand was the grip that a substance like caffeine could have on him.

I certainly couldn't write for the first few weeks. I just didn't have a - my mind just didn't focus. I didn't have this ability to think in a linear way. I really felt like - I've never had an attention deficit disorder, but I felt like I had acquired it. Distractions would come in from all places that never would have been a problem. I don't usually have trouble concentrating. That persisted for a long time, that inability to concentrate. And I just felt - and this is really weird to say - I just didn't feel myself. And it's weird to say because, does that mean myself is my caffeinated self? Is that my baseline? I guess so. And this other self, which was not as pleasant to be, was my real self, my uncaffeinated self.

What Pollan is describing are the symptoms of withdrawal. It's the same as anyone who is cutting back on an addictive substance. But over time, he noticed something different, this sort of shift.

I was sleeping like a teenager again, You know, I could sleep longer and deeper. And that was the big upside to quitting.

There were benefits to this experience for him. But, after three long months, Pollan says he was still ready to go back to his old routine.

That first cup was mind blowing. It was so good. It was one of the best of any drug experience I've ever had, and it was truly ecstatic.

Now, if you know anything about Michael Pollan, you probably know this isn't the first time he's experimented on himself. Pollan used psychedelics in the process of writing his book, "How to Change Your Mind." He was researching how changing the habits of the brain could be therapeutic for people facing addiction and depression. But Pollan says caffeine is a unique drug, mostly because it's so common. So many of us consume caffeine every day, whether it's in the form of coffee or soda or even chocolate. Pollan calls it the most commonly used psychoactive drug in the world.

And I had no idea it was that powerful. And most people don't because they're already in this caffeine, you know, culture. So I highly recommend getting off caffeine, if only to have that experience of getting back on caffeine. And if you have doubts that it's a powerful psychoactive drug, they will go away.

Now, to be fair, I don't think most of us would put caffeine in the same category as mushrooms or MDMA. And to be honest, I was even a little surprised to hear Pollan referred to caffeine as a psychoactive drug. I think it raises lots of questions. What does it mean for so many of us who consume it every day? Is it possible to have a healthy relationship with the substance? On today's episode, we're going to talk about the caffeinated brain. I'm going to sit down with Michael Pollan to learn more about the science behind how caffeine actually alters our brains, and why he says caffeine has altered the course of human history even. And his tips for making the most of your morning cup of coffee, or two. I'm Dr. Sanjay Gupta, CNN's chief medical correspondent. And this is Chasing Life.

All right. To be honest, I know a lot of you listening may already be thinking, "there's no way I'm giving up my daily cup of coffee." And that's okay. You don't have to. This is not the type of episode where I'm telling you to throw out your coffee machine or give up your morning latte. Quite the opposite. In fact, that's what I like about Michael Pollan. He takes this pretty nuanced and scientific approach to things. In his latest book, which is called "This Is Your Mind on Plants." Pollan dives deep into how plants and plant-based substances from cannabis to caffeine alter us and alter our minds. He says before we begin to understand the impact caffeine has had on us as individuals, we do have to take a step back and think about the bigger picture. We need to think about why we as humans are so drawn to altering our brains with substances in the first place. As you might guess, it starts in the brain with these specific receptors that send messages to the rest of the body.

I've always been interested in these psychoactive substances that plants produce. I think it's just a really curious fact of nature that we have these plants in the world that produce these compounds that just happen to unlock receptors in our brains. What are the odds of that? Why are they doing that? Why did that involve? And the related question is, why do we why are we so attracted to them? What is it about us that is so eager to change the experience of consciousness? Why are we not satisfied with everyday, normal consciousness? And we're not the only animal too. I mean, other animals, you know, like to change consciousness, too. And they they find plants in the natural world that change how they feel, including caffeine. So so those are the two related things. I just think that's one of the more interesting facts of natural history.

What are we to make of the idea that we do have these naturally occurring receptors in our in our body? Well, what does that mean?

Well, I think we're kind of hijacking them when we use these plant drugs. We have receptors for different reasons. And I think that the drug experience is a case of kind of hijacking those receptors and doing something else with them.

What I've always struggled with a little bit is why we have receptors for things we don't make. Was it that the body evolved to naturally and expectedly be stimulated by these extraneous exogenous substances such as caffeine or other substances?

Well, we do have receptors for caffeine. Well, actually for adenosine, right, which is the chemical that this receptor - we have adenosine receptors that respond to this endogenous chemical called adenosine. And it just so happens that caffeine fits into that receptor. But it's an accident of evolution. It happened a long time ago. Many of these plant-based chemicals are alkaloids that are defense chemicals. They're produced by the plant to defend itself. Plants rely on chemistry because they can't move, right? So they can't run away. They can't attack. So they have these chemicals they produce to take care of a lot of their needs, including defense. So it's a really wise strategy, I think, to just mess with the brains of your predators rather than kill them outright. And so that may be why the chemicals that had that effect were the ones that were preserved in evolution. My insight into this came through a personal anecdote of I had a cat named Frank who really had a problem with catnip, and I had planted some catnip in my garden. And every evening when I went down to my garden in the summer to harvest for dinner, Frank would follow me into the garden - it was fenced - and he'd look up at me. And what he wanted was to be reminded where the catnip was. Because every day he forgot. Yeah. And the reason he forgot is he got so high on catnip and would roll around in it. And that was, you know, and then he was useless. So it succeeded in, in, in repelling him as a predator without killing him.

Maybe he was asking for permission. Who knows?

It could be that, too. You're right.

But it is fascinating when you sort of look at the interplay between some of these plants, the mind altering effect that they might have on insects, even some of which are pollinators, you know, So you'd think there's this really symbiotic relationship, but it gets complicated. You write about spiders and this experiment that took place at NASA. Can you just tell us about that?

Yeah. Some very creative biologist at NASA years ago decided to give spiders a bunch of psychoactive substances to see what would happen. And he gave the spiders LSD and he gave them caffeine. And I forget what else he gave them, alcohol? And the most kind of screwed up web - they all made defective webs, right? They lost their symmetry. Bugs could get right through them without any problem. But even more weird and ineffective than the LSD web was the one on caffeine. And it was like this weird cubist picture that would be completely ineffective. So it was proof, though, that this chemical, very common in the natural world, certainly helped, you know, plants defend against spiders and probably lots of other insects as well.

Is that part of the defense mechanism you're talking about or what do you think? If you have to teleological, you contrive what's going on there?

I think it is part of the defense mechanism. The spider has essentially been disabled by this chemical. It can't do its work. It's drunk, you know, and it's completely ineffective. So I think it suggests that the defense chemicals operate not simply by poisoning or killing off the insect, but by messing with its mind. And this is one of the most fascinating things I learned writing about caffeine is that there are certain plants that produce caffeine in their nectar. Hmm. Now, that makes no sense, because nectar is about attracting insects, right? It's not killing them or disabling them. So it turns out that bees really like caffeine, too, and that they will be attracted to plants that produce caffeine in their nectar, in small amounts that are not poisonous. And there's been some really interesting research done on this in Europe. And what they found is that the blossoms that produced caffeine in the nectar were favored by the bees. They were more likely to pay that flower a visit. And, even better, they were more likely to return to it and remember it. And as the researchers said, it increased pollinator fidelity. Basically, they became more loyal to that kind of flower than any other kind of flower. Almost to the point of that, it was a disadvantage for the bees because they would return to those caffeine flowers long after there was nothing left. No more nectar, no more caffeine, no more pollen. So it made me realize that we as humans are like those bees being manipulated by this plant and the chemical it's producing to do a job for it. And if you think of what have what humans have done for the coffee plant and what humans have done for the tea plant, you know, we've gone to enormous lengths to increase their range, expand their habitat, move them around the world. It's been a brilliant evolutionary strategy on the part of both the coffee plant and the tea plant.

And has it been a reciprocal relationship, I mean, boon or bane for human civilization? Caffeine?

I would say in the case of caffeine, it's been a boon. Unless you don't like, you know, things like the Enlightenment and capitalism and the Age of Reason, which all of which benefited enormously from the arrival of caffeine in Europe. So one of the things that's really interesting about caffeine is we can chart before and after, we can see its impact on our species and on our civilization in a way we can't with alcohol. People have been drinking for like, you know, millennia, long before recorded history. Caffeine does not come to the West until the 17th century, and specifically it arrives in England in three forms coffee, tea and chocolate all show up in England in the decade of the 1650s. So we have a real sense of what life was like before and after. And people notice the change. I found sources talking about a 'new sobriety.' People were drinking less and going to coffeehouses more. So there was a change in in consciousness, you could say, from a very addled, drunken state of consciousness, because we have no idea compared to how much people drank in those days. Alcohol was safer than water, right, because water carried disease. So even kids were given mild forms of alcohol, like apple cider and hard cider and things like that. And people drank morning, noon and night. It's not like people stopped drinking, but they spent a lot more time in coffeehouses than taverns, and they were drinking a lot more caffeine and less alcohol. And this had a huge effect. And so you have these interesting developments after caffeine comes in. You have the age of reason in Europe, in England, you have the Enlightenment in France. And you can chart by looking at individuals and their relationship to caffeine. That you know Diderot who wrote the first encyclopedia, he did it in a cafe, drinking coffee. It never would have gotten completed in a tavern. And then capitalism. It's the perfect drug for capitalism. It makes us work harder. It makes us more precise and more focused. And it also and I think this is really important for the Industrial Revolution, it disconnects us from the circadian rhythms, you know, the fact is before caffeine, people woke up with the sun and they pretty much stopped working when it got dark. And suddenly you didn't have to do that. You could have a night shift. You could have an overnight shift because you could keep people awake with caffeine. So this is incredibly, so you could just, you know, extract much more value from the average worker if you gave them caffeine. And that, you know, to fast forward a bit, brings us to the coffee break. Think about it. Your employer gives you a drug and time in which to enjoy it all for free. And the reason is that employers found that workers did a better job when they were caffeinated.

Are you altered when you are caffeinated?

Yes, you are in ways that are subtle compared to alcohol or psychedelics or other drugs, but just as distinctive. There's something transparent about consciousness on caffeine. Things seem they don't seem like they're distorted in any way, but they're sure different. And the way you can tell is by giving up caffeine for a period of time. Most of us, and I'm talking about the 90% of humanity that has a daily relationship with caffeine. It is the most widely used psychoactive in the world. And it's the only psychoactive we give to our children, by the way, in the form of caffeinated sodas, which is kind of a crazy idea. Anyway. So we start kids very early on their caffeine addiction and then they transition into coffee and usually or perhaps tea, it starts kicking in. As soon as you wake up, you are going through withdrawal and the coffee relieves you of those symptoms. And that's the main experience most of us have, is to be relieved of those withdrawals and to be with weight, to be relieved of those withdrawal symptoms. I need a cup of coffee actually, right now, but I'm done today.

Have you had yours today?

I have, but I try to knock off by noon. And that that's very different than if you are a caffeine virgin. Let's say you don't use caffeine and you have one cup. You will get in touch with what a powerful shift in consciousness that is.

If you've been listening closely, this may be blowing your mind a little bit here. Thinking about caffeine as something that can shift consciousness. That's something you probably never really considered. And as Pollan points out, for so many of us, again, this is a substance we use every day. So I think the question is, what does it mean then, on a practical level, how can we use this drug for good? I'll ask him after the break.

And now back to Chasing Life and my conversation with best-selling author Michael Pollan.

You talked about this earlier, but again, you have caffeine. You have these receptors in your body for adenosine, which is a chemical that sort of prepares your body for sleep. How do you how do you describe what caffeine then is doing in the brain?

Yeah. So one of my big questions and this is true with any drug, is it is is there a free lunch here or do you pay a price? In general with drugs, we pay a price of some kind. And it turns out to be true in caffeine as well. So what the caffeine is doing is blocking the action of adenosine. During the course of the day, your adenosine levels gradually build up, preparing you for sleep. They increase what is called sleep pressure. But if they're blocked, they're not having any effect. And so that's kind of what caffeine is doing. It's stopping the action of this chemical that otherwise would be making you slow down and prepare for sleep. The problem is the adenosine is still circulating in your brain. And in fact, its levels are rising. So as soon as the caffeine wears off, as soon as it's metabolized, you get hit with more adenosine than you would have before. So you're really borrowing against the future when you use caffeine, that the energy you feel you're taking from the future. And, you know, that's something to keep in mind, that if you drink a lot of caffeine to stay awake, you're going to crash at some point because the adenosine will have its way.

So the adenosine in response to taking caffeine, you might actually make more of it. So when then the caffeine starts to wear off, you suddenly have a lot of adenosine around. And that's the crash?

Yeah, that's the crash. Is the adenosine getting into those receptors as the liver basically takes the caffeine out of your body? The problem, though, in terms of sleep is that caffeine stays in your body a long time. It has a half-life of I forget how many hours, but it has a quarter life of 12 hours, which means the caffeine you ingest at noon in the form of a cup of coffee or tea, 25% of it will still be circulating at midnight. So you're not quite at base level at that point. And that is, you know, I went looking for like, what's wrong with this drug? What does it do to you that's bad? Why should we worry about it? And I looked at a lot of research, and over the years, people have proposed that it's implicated in heart disease and implicated in high blood pressure, none of which holds up. Most of the health effects are actually positive. Caffeine, or, I should say, to be more precise, caffeine containing drinks, such as coffee and tea, have a lot of very positive health effects. They help with cardiovascular disease. They are correlated with lower rates of Parkinson's disease. There's a whole slew of things in certain cancers, too, that they appear to help with. But that may not be the caffeine that's responsible. It may be, and this was the second most amazing fact I learned researching caffeine, is that coffee and tea are the biggest source of antioxidants in the American's diet.

Hmm.

That's kind of incredible. You should be getting them from vegetables and other plants. All plants have antioxidants, but that we're getting most of them from coffee and tea tells you we're not eating a lot of vegetables, which of course, is the case. So anyway, the only real serious negative is what it does to your sleep.

That's interesting. Is there a dose makes the poison analogy here? I guess there is with everything. Right. But is it everyone different? I mean, you have a couple of cups, maybe a morning, but what is the right dose, if you will?

There's an interesting statistic based on a study, or maybe several studies I'm not sure, that found that caffeine was antidepressant up until about eight cups a day. After eight cups a day, it had the opposite effect. And suicidality, your inclination to suicide went down until you got to eight cups and then it went up. So there is a curve there. But I think each of us has to find where it is for ourselves, because I think that I think response to caffeine is pretty variable.

I think when I read the book, Roland Griffiths was the one who said, you know what, if you really want to write about this and understand the impact of coffee, go cold turkey for a period of time. He is also the person who I think was responsible for getting caffeine withdrawal into the DSM. And so if caffeine withdrawal is real, is caffeine addiction real? Is that a real thing?

Yes, it is a real thing.

And what does it mean in this regard?

Well, it's a drug that you can't stop taking without suffering side effects. And it's a drug that you crave. And it's a drug that you will take to stem the side effects of withdrawal. So, yeah, so it fits pretty well. There's also some dopamine release. So yeah, I think it does category. It does fit in the category of addictive drugs. And I don't think it's an accident that Roland Griffith who is, you know, a psychopharmacologist who's studying. He had been studying drugs of abuse for a long time, would turn his attention to caffeine. It's a drug that happens to be socially acceptable. But we should keep in mind that the status of all drugs is very much culture bound and that at different times in our history, you know, the women fighting for temperance, you know, who were, you know, using their axes to break down saloon doors because they hated alcohol so much and finally got it banned in the thirties. They were kicking back with potions that had opium in them and cannabis. And they didn't. They thought nothing of it. Opium and cannabis were perfectly legal during temperance. So there is, you know, there is a wave of what we decide to approve as a drug that socially acceptable and what we reject. And it's constantly changing. It's changing right now around cannabis. And so, you know, there has there have been one or two little efforts to ban caffeine in history. They were really unpopular. Charles II when he came into at The Restoration in England, I forget what year it was. He was really nervous because the people who drank coffee were people who plotted and talk politics all the time. They were going to coffee houses. And in fact, the French Revolution was really, you know, the mob that stormed the Bastille had been hyped up on caffeine, not alcohol. And so there was a worry that the kind of conversation fostered by caffeine was politically dangerous. So, Charles II, he was a pretty weak monarch when he came back, tried to ban caffeine and everybody just ignored him. And he withdrew the ban after like two weeks. So it's been a tough one to I don't think we'll see caffeine prohibition anytime soon. But other drugs, yeah, they go up and down in public esteem and it doesn't, sometimes it has to do with health and health benefits. But a lot of it, it's just, ah, we tend to moralize, you know, these substances and we're uncomfortable with the idea. We like to change consciousness via chemicals. It just doesn't seem, you know, quite kosher.

We're going to refer to caffeine as a psychoactive substance. It's something that can caffeinated your body, caffeinated nature, your brain. They put it in the same category as as cannabis, as LSD, things like that. And it makes me, you know, wonder, should we be talking about this more in a more serious way? I mean, are we too casual, if you will, about the the impacts of caffeine, good or bad?

No, I don't think so. I looked into this whole question of, you know, what are the health effects, good or bad, public health or personal health? I didn't find a lot of evidence saying that we really should, you know, curb our use of this or regulate caffeine. To the contrary, and the only place where I think you can make that argument is kids. And we need to do more research to understand what affect caffeine. You know, we're dealing with ADHD, you know, at very high rates among kids. How much of that is the result of kids using caffeine? So I think we should resist our tendency to moralize these substances. There are definitely drugs that are huge public health problems. Fentanyl is a great example, but there are a great many drugs that are illegal, that have huge benefits. And psychedelics, we're now learning, is one of those. Is a category of drug that has great value in healing mental illness. So I think it's an ongoing conversation around psychoactives. I think they're very charged for us. We you know, maybe because we're Puritans in this country and religions often have prohibitions on mind changing substances. Think of the Mormons who don't drink caffeine or don't drink it in its hot form. I think they can drink in it in the form of soda. I might be mistaken. But I see our taboos around drugs as being very culturally based, often not scientific at all.

In terms of tips now for our listeners regarding caffeine, do you find, after all the research you've done in your own personal experience, is there an ideal way to consume caffeine?

Well, I the first thing I would say is experiment with getting off it. Take Roland Griffith's advice. If you really want to understand a drug and your relationship to it, you have to get off it for a period of time. See what those cold turkey symptoms feel like, and you'll realize how much you miss it and how deeply woven it is now part of your life. So that's one tip. The other tip, though, if you want to get off it for the purpose of getting back on it and having the kind of ecstatic experience that first cup of coffee can be. Taper. Don't go cold turkey. It's not that hard if you're willing to gradually step down the amount of caffeine and move toward a decaf cup of coffee, and then off of that, you won't have a lot of symptoms. And yet, after a couple of weeks of being off caffeine, first, you'll save a lot of money because we're now spending many dollars a day on our caffeine habit because nobody makes coffee themselves at home anymore. It seems like that's a kind of painless way to have that very positive experience of the first cup of of caffeine. My biggest advice would be, be aware. You know, when are you knocking off? When when is your last cup of coffee or tea during the day? How does that correlate with your sleep? Just make that connection.

Michael Pollan is a science writer, and most recently, the author of "This Is Your Mind on Plants." It's a book about psychoactive plants like caffeine and how they might impact our brains. You know, I got to say, after talking to him, I don't think I'm going to look at my morning cup of coffee quite the same way. I think I might even try the caffeine fast for myself just to see how my body would respond. That was one of my biggest takeaways from my conversation with Michael, and I think it's worthwhile for all of us to stop, take a minute and understand how any substance we use, even if it's used daily, how it's really affecting us and our brains. Sometimes because we are so used to these substances, we don't really stop and reflect on what exactly it's doing to our brains. And in a world that's so fast paced, sometimes it's worth slowing down and really reflecting on our habits, even if it's something as simple as a morning cup of coffee.

Coming up next week on the podcast, The Menopausal Brain.

I'm in my forties and I'm premenopausal, which means I have a regular cycle and this is a great time to prepare. So I do a ton of stuff. My husband thinks I'm nuts.

Thanks for listening.

Chasing Life is a production of CNN Audio. Our podcast is produced by Eryn Matthewson, Madeleine Thompson, David Rind, Xavier Lopez and Grace Walker, Our senior producer and showrunner is Felicia Patinkin. Andrea Kane is our medical writer and Tommy Bazarian is our engineer. Dan Dzula is our technical director and the executive producer of CNN Audio is Steve Lickteig. Special thanks to Ben Tinker, Amanda Sealy and Nadia Kounang of CNN Health.