Michael Pollan Explains Caffeine Cravings (And Why You Don't Have To Quit)

TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. Most of our team is working at home now, including me, so occasionally we're going to need a day to catch up, and today is one of those days.

So today we're going to replay one of our favorite and most popular recent interviews. It's about caffeine. After trying psychedelic drugs for research on his book "How To Change Your Mind: What The Science Of Psychedelics Teaches Us About Consciousness, Dying, Addiction, Depression And Transcendence," my guest Michael Pollan gave up caffeine as part of his research for his new audiobook "Caffeine: How Coffee And Tea Created The Modern World."

If you're a coffee drinker, you won't be surprised to hear how hard it was for Pollan to give it up. His new book is about how caffeine affects the mind and body, why we feel so bad when we stop drinking it, how caffeine benefits the plants that produce it and how coffee and tea's spread around the world was intertwined with imperialism and slavery. Pollan has written many books about the impact of food on our bodies and how the methods we use to grow food and raise livestock affect the environment. His new audiobook "Caffeine" is an audible original.

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GROSS: Michael Pollan, welcome back to FRESH AIR. When we last left off...

(LAUGHTER)

GROSS: ...You had just finished your exploration of psychedelic drugs, and it was an exploration conducted through research books as well as through taking the drugs. So do you see a connection between your exploration of psychedelic drugs and their impact on - you know, on the mind and body and caffeine?

MICHAEL POLLAN: Well, absolutely. This is kind of a follow-on. You know, my exploration of psychedelics got me very interested in consciousness and, you know, whether there is just one form of normal everyday consciousness or are there many. And it occurred to me after working on these extraordinary, you know, and very disruptive drugs, like psilocybin and LSD, that there was another drug hidden in plain sight in my life, and that was caffeine in the form of coffee and tea. And I thought, well, why not explore that relationship? Here's - you know, here's a drug we use every day. Eighty percent of the world's population, including children, use caffeine every day, yet we never think about it as a drug or an addiction. But that's exactly what it is.

GROSS: But, you know, we think of caffeine as a stimulant that helps you stay awake or wake up. Most people don't think of it as a psychoactive drug, a drug that affects consciousness or mood or behavior. So in what sense is caffeine a psychoactive drug?

POLLAN: Well, it encourages a certain kind of consciousness. It makes us more focused. We can see - you know, I mean, if you think about consciousness as having different degrees of narrowness or focus versus taking in information from, you know, the whole field, coffee and tea help us focus, concentrate. And they're clear. They're very transparent. I think one of the reasons we don't think of being caffeinated as an altered state of consciousness, unless we use so much that we're jittery, is that it's weirdly transparent. Whereas, you know, other drugs you use and alcohol, they have a kind of physiological noise to them that - and you know you're on them. But caffeine is a little different. It's very subtle that way.

But yeah, it helps us stay awake, but it does a lot of other things, too. And this has been proven. I mean, there's studies that show that people's both mental performance and athletic performance are improved by coffee and your memory. If you have a cup of coffee after you've learned something or read a textbook chapter, you are more likely to test better on it the next day.

GROSS: Wow. So you tried to learn about the effects of caffeine by giving it up and seeing what impact it had to basically go into caffeine withdrawal. Why did you decide to give it up? Who convinced you?

POLLAN: Well, there was a researcher named Roland Griffiths who I actually met doing my research on psychedelics. He's a preeminent psychedelic researcher at Johns Hopkins, but he's also, as it turns out, the preeminent caffeine researcher. That was the last phase of his career. And I started interviewing him, and he said, look - you're never going to understand your relationship to this drug unless you get off it and see what it's really about. And I think this is true for any kind of habit. Until you try to break it, you really don't understand its hold on you. So it was kind of a challenge. You know, if you really want to write this piece and understand caffeine in your life, you've got to get off it.

And I decided to get off it the hardest way possible, which was cold turkey. You know, you can taper off of caffeine, and it's not that hard. Just, you know, go to, you know, half-caf and then quarter-caffeine and decaf, which has a little bit of caffeine in it. But I wanted to see what withdrawal would be like. And in fact, Roland Griffiths is responsible for getting caffeine withdrawal as a mental disorder into the "Diagnostic and Statistical Manual" No. 5. And so I did it. I put it off as long as I could. I dreaded it. I love my coffee. It's indispensable to my morning ritual and to my ability to write and read and think. But I did it for the piece. I did it for the readers, or the listeners in this case. And...

GROSS: So how were you transformed when you went off caffeine cold turkey?

POLLAN: (Laughter) It was really hard. The first couple of days were - I just couldn't focus. I was irritable. I lost confidence. The whole book seemed like a really stupid idea. And loss of confidence is actually listed as one of the symptoms of caffeine withdrawal. But the thing that really struck me was that - you know, I've never had ADD. I can focus pretty well. I felt like, oh, this is what ADD is like. I can't keep stuff out of the peripheries. You know, the peripheral information and sense data keeps rushing in and getting in the way of staying on - I felt like I was a horse that had taken its blinders off, and suddenly I could see in too many degrees of circumference.

And so that was a real problem for working. I really had trouble sitting and writing and staying still. And, you know, after a few days, this began to lift. I felt as though there were a - and I think anyone who, you know, delays having their morning cup of coffee knows what I'm talking about - but there was a kind of a sense of a veil or fog that had descended between me and reality. I was just kind of muzzy-headed. And that gradually lifted. But I have to say, even weeks later, I felt like there was a little mental hitch between me and reality. I felt as if, you know, this wasn't my natural language (laughter). I was speaking in another language, which never goes that well or that smoothly. And that sense of transparency was lost.

I got over it, eventually, and I wrote a big chunk of the piece without the influence of caffeine. But it was an interesting three months. And, you know, I recommend it, actually. I think it's a really interesting exercise. You understand that you are, indeed, addicted. And that isn't necessarily a bad thing. You know, I think the word addiction has a lot of moral baggage attached to it. But as Roland Griffiths told me, you know, if you have a steady supply of something, you can afford it, and it's not interfering with your life, there's nothing wrong with being addicted.

GROSS: Was your sleep changed when you gave up caffeine?

POLLAN: Oh, yeah. I forgot to talk about that, yes.

(LAUGHTER)

POLLAN: It was amazing. I was sleeping like a teenager again. I would pop off and just sleep through the night, which I don't do that often. And I had some great sleeps. And I guess that was the big compensating benefit of giving up caffeine. And of course, one of the things we know about caffeine, everybody knows, that it does mess with your sleep, in ways I didn't fully understand till I started exploring that. But sleep - you know, caffeine is the enemy of good sleep.

GROSS: Ways you didn't fully understand, like what?

POLLAN: Well, I always figured, if I can have a - oh, let's say I decide to, you know, go crazy and have an espresso after dinner and - oh, gee, I can fall asleep. I slept that night. So maybe it's not a problem for me. Well, it's a problem in ways we don't perceive because caffeine undermines the quality - not necessarily the quantity, but the quality of our sleep, and specifically one very particular kind of sleep, which I'd never heard of before, called slow wave or deep sleep.

This isn't REM sleep, where you're having dreams, or light sleep. This is a really deep place you go for not that long a part of the night, but it's really important to your mental and physical health. It's where these slow waves start radiating from the front of your brain into the back, and they kind of harmonize all the neurons, get them on the same page. And it's where you kind of take memories from short-term working memory and put them in their proper place. It's like cleaning up the desktop on your computer by the - at the end of the day.

And Matt Walker, you know, the psychologist who wrote "Why We Sleep," you know, is - thinks that this is very important to our health, to have sufficient amounts of deep sleep. And as we get older, we have less of it naturally. And coffee or tea cuts into that, even if you stop drinking it, say, at noon because caffeine has a very long half-life and quarter-life. So, for example, the caffeine you ingest at noon, a quarter of it is still circulating in your bloodstream at midnight. So it's still around. And this is the subtle and perhaps insidious effect it's having on you.

GROSS: You said that if you're a coffee drinker, you go through a withdrawal every night, and then when you wake up in the morning, the coffee arrives just in time to prevent the withdrawal symptoms from getting worse. So really? You go through withdrawal that quickly?

POLLAN: Yeah, it's beginning when you wake up. I mean, you haven't had coffee since sometime - or tea since sometime the day before. And...

GROSS: How often does coffee want you to have it?

(LAUGHTER)

POLLAN: Well, once a day. It - the cycle - they're called the pharmacokinetics - of caffeine seem very well synchronized to the circadian rhythms of the human body. So that, you know, it's really amazing that you don't go through withdrawal at, like, 2:00 in the morning, when it's out of your system, and it doesn't wake you up saying, you got to have coffee. Nobody feels like coffee in the middle of the night.

But in the morning, you are beginning to feel - you know, all those people who tell you, you know, I'm not civil, I'm not fit for, you know (laughter), human conversation until I have my cup of coffee, they're beginning to go through that withdrawal. They're starting to feel a little off, that muzziness is coming in. Maybe they have a headache. Maybe they're a little irritable. And then they have that cup of coffee, and the pleasure they're getting from it, I learned, is not simply the lift, the euphoric lift of the drug; it's the suppression of these symptoms of withdrawal, and we go through that cycle.

And one of the things you learn when you take a caffeine fast, as I did, is that the experience of caffeine's very different to a caffeine virgin or a restored caffeine virgin, as I was, than it is to someone who's addicted. They're - those people are getting a little bit of lift, but mostly what they're getting is the relief from these symptoms that are about to come down on them. And that feels pretty good. You're back to baseline. But when you're off for a few months, man, it's something else. It's a very powerful drug experience, and I was not prepared for it at all.

GROSS: Is there a relatively simple, not terribly sciencey (ph) way of describing...

POLLAN: (Laughter).

GROSS: ...How caffeine operates in the brain to give us the wakefulness...

POLLAN: Yeah.

GROSS: ...The hit that it gives us and also keep us awake?

POLLAN: Yeah, it's pretty simple. We have a neurotransmitter called adenosine, or adenosine, that over the course of the day, levels of it rise, and its job is to gradually make us tired, create what's called sleep pressure, so eventually, you know, we turn out the lights and go to sleep. There is a receptor that the adenosine fits into. And as it turns out, caffeine fits into the same receptor, and it gets there before the adenosine has a chance to. So it essentially blocks the action of that neurotransmitter, and so you never get the signal that you're tired.

Eventually, though, the adenosine, it's not like it goes away; it keeps building up, the level in your bloodstream keeps building up so that when the caffeine is finally metabolized and the receptors are available again - voom - you get hit by, you know, a flood of adenosine, and you get really tired. And what would you do then? Well, you'd try have another cup of coffee and start the cycle all over again. So it's a pretty simple mechanism. That's what keeps us awake. That's the alertness of caffeine. But it does also act on some other networks, such as the dopamine network, and that's part of what gives us the euphoria.

GROSS: All right. Let's take a short break here, and then we'll talk more about caffeine and coffee and tea. And if you're just joining us, my guest is Michael Pollan, and his new book is really an audiobook. It's an Audible Original. It's called "Caffeine: How Coffee And Tea Created The Modern World." We'll be right back. This is FRESH AIR.

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GROSS: This is FRESH AIR. Let's get back to the interview I recorded in February with Michael Pollan about his new audiobook "Caffeine."

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GROSS: You point out that coffee is bound up with the sins of slavery and imperialism.

POLLAN: Yeah. I mean, look - there's a really ugly history behind both of them. You know, the early coffee plantations in Brazil were all - the workers were slaves. But even later, when you have post-slavery Central America, these were brutal places to work. The thing about growing coffee and tea is you need a lot of labor because it - you know, the shrubs have to be pruned. Picking them - I went coffee picking in Colombia, and it's really hard work. And it's kind of a spiky plant, and it grows on such a steep hillside you can't get your footing. And it took, you know - I mean, basically, there is a - I'm - right now, I'm reading this history of coffee plantations in El Salvador. And to produce all the wage labor they needed to take care of the coffee, they essentially had to starve the Indians that lived on this very fertile land and were eating from the land without a lot of trouble. And they ripped out all the edible plants, so the Indians were forced to work on the plantations. It's a very dark history.

And like a lot of things, you know, we're participating in this commodity change. We have no idea what's behind it. I mean, who among us has seen a coffee plant or a tea plant except in, you know, photography? But at the other end of those food chains has often been quite a bit of brutality. And of course, coffee and tea drove demand for sugar, and sugar was at the very heart of the slave trade in the Caribbean.

And then you have another moral stain with - I don't mean to bum people out while they're drinking their coffee and tea. But the tea - you know, when the English started importing tea from China in the 1700s, it became very popular. In fact, it's hard to imagine an industrial revolution without tea to support - to keep all those workers going. But the Chinese, they didn't have any goods they wanted to buy from England. So the English had to pay in silver and sterling, and it led to this enormous balance of trade deficit.

So what did the English do? They came up with this very clever idea. They had this colony in India, and they started growing tea in India, and they also started growing opium. And they essentially forced the opium into the Chinese market, addicted tens of millions of Chinese, undermined that great civilization all so they could improve their balance of payments problem with the Chinese and trade opium for tea.

GROSS: So was the goal just to improve the balance of trade payments? Was the goal an economic one? Or did they intend to actually addict people in China?

POLLAN: I don't know it was their intention to addict, but that was certainly the effect. Yeah, they just needed a product to sell in China. And even though the Chinese forbade it, they just smuggled it in and then fought a war to open up ports so they could continue to dump opium on the Chinese. So, you know, I mean, the irony is that the Chinese mind had to be dulled so the English mind could be sharpened with caffeine.

GROSS: As you point out, there was a time when most Americans drank coffee that came in a can or instant coffee that came in a jar, which seldom tasted anything like coffee (laughter).

POLLAN: That's for sure.

GROSS: So how did we get from, you know, ground coffee in a can to the kind of deluxe coffee that so many people buy now? I don't remember, when I was growing up, having that option.

POLLAN: There are two big strains of coffee plants. One is robusta. As its name suggests, it's very robust, easier to grow, less touchy as a plant. But it produces very bitter coffee and - high caffeine, but bitter coffee. And that was kind of the mainstay. That's what you got out of those cans of coffees - Maxwell House or Hills Brothers or whatever it was - and that was what went into instant coffee.

There's a kind of coffee revolution that begins in the '60s, and it begins right here in Berkeley, where I am, at Peet's. Peet's is now a big chain all over the country. And Alfred Peet was a Dutchman who was living in California and decried the quality of coffee. He'd had better coffee at home. And his father, in fact, had been a coffee roaster. So he starts importing arabica beans, the higher-quality, more-difficult-to-grow beans. And he also starts roasting them very carefully, slowly and long, creating something that's much more delicious than the way most coffee was roasted before.

And Peet was an - you know, one of these obsessives for, you know, the quality of what he was doing. And he had a shop right near Chez Panisse, around the corner on Walnut Street and Vine, and this became a real destination. And he became known as the great coffee roaster. And he was very generous about his knowledge. So he trained, in fact, the people who started Starbucks and a great many other, you know, artisanal coffee places. And it really all grows from, you know, the work of that man in that shop. He taught us, really, how to appreciate better coffee.

And he got us used to, you know, spending a few dollars for a cup instead of 25 cents or 50 cents for, you know, the normal diner coffee you used to get. So there's been a real upgrade in the quality of coffee in our time. And we seem comfortable spending, you know, $5 for an espresso drink. It's quite remarkable.

GROSS: We're listening back to the interview with Michael Pollan that we recorded last month. His new audiobook is called "Caffeine." After we take a short break, we'll talk about how the caffeine affected his mind and body when he started drinking coffee again after having given it up for months as part of his research. And jazz critic Kevin Whitehead will review a new album by guitarist Jeff Parker. I'm Terry Gross, and this is FRESH AIR.

(SOUNDBITE OF SONG, "CIGARETTES AND COFFEE")

OTIS REDDING: (Singing) It's early in the morning, about a quarter till 3. I'm sitting here talking with my baby over cigarettes and coffee, yeah. And to tell you that, darling, I've been so satisfied...

GROSS: This is FRESH AIR. I'm Terry Gross. Let's get back to the interview I recorded last month with Michael Pollan about his new audiobook "Caffeine: How Coffee And Tea Created The Modern World." It's about how caffeine affects the mind and body and about how coffee and tea became popular around the world. Caffeine is the world's most widely consumed psychoactive drug. Pollan's previous book "How To Change Your Mind" was about how psychedelic drugs alter consciousness and how they're now being used experimentally to treat addiction, depression and help the terminally ill face death. Pollan describes himself as writing about the places where culture and nature intersect - on our plates, in our farms and gardens and in our minds.

(SOUNDBITE OF ARCHIVED NPR BROADCAST)

GROSS: You visited a coffee plantation in Colombia. What's the work like? Like, you picked coffee beans. What do you have to do to pick coffee beans? What's...

POLLAN: Yeah.

GROSS: Yeah.

POLLAN: I mean, I picked coffee beans for about 25 minutes, just to be clear (laughter). This wasn't like I went undercover and I was - I had this job. But I wanted to see how it was grown. And I went to this finca outside of Medellin and Columbia and spent a day with the coffee farmers, and it was really interesting. It's very hard work. It's much harder than many other kinds of agriculture.

Coffee grows on a very steep hillside because it needs very - it needs lots of water, so it needs to be in the tropics, but it needs lots of very good drainage, too, which you only get on a hillside. And it's this spiky shrub that has to be pruned. And you are - there are rows that you walk between the rows of coffee plants that are so steep you can barely find your footing. Meanwhile, you have this basket that's suspended from your shoulders, and you're reaching in and picking the red berries and leaving the green berries. And you're doing this on a hillside that's just incredibly hard to move around on.

And then you take them down to a processing shed, and they have to be, you know - you have to take off the pulp. They look like cherries or cranberries. They're red, and they have a pulp that actually tastes really good. It's very sweet and has a coffee taste. I don't know why people don't make preserves with it or something. It should be used for something. And then it has to be dried and fermented. There are many, many steps.

So it's a very demanding and - plant. And it's very picky. It has to have exactly the right altitude, water, angle, you know, all this kind of stuff, which is concerning now because coffee faces a tremendous threat from climate change. You know, there is a narrow band of conditions that make coffee happy. And the estimates now on the climate scientists - and this will be alarming to the fellow addicts out there - is that 50% of the coffee-growing regions will not be able to support the coffee plant by 2050. So capitalism may be killing the golden goose as climate change undermines coffee production. And we may go back to robusta, which, you know, can grow and is a little less picky about its environment.

So we may look back and say we lived in this, you know, golden age of good coffee that lasted from 1966 to 2050, and then it will be downhill from there.

GROSS: When we started our interview, you were telling us how you gave up coffee cold turkey when you were writing your book "Caffeine" because you wanted to know what's it like - what impact does caffeine have on you and, to find out, you stopped it to see what the difference was. And to see how addictive it was, you did it cold turkey, so you could get the full force of ending your addiction.

POLLAN: Yes.

(LAUGHTER)

GROSS: And then after how many months you decided to start drinking?

POLLAN: After three months, yeah.

GROSS: And...

POLLAN: It was three months on herbal tea.

GROSS: And when you started drinking it again, was that still part of the experiment, or just 'cause...

POLLAN: Yeah.

GROSS: ...You couldn't bear to live without it anymore?

POLLAN: Oh, no. No, it was part of the experiment. I went as long as I could. But I knew before I finished the book that I would want to describe, you know, getting back on caffeine. I fully intended to get back to it. There - I didn't learn - you know, aside from the sleep issue I mentioned earlier, there are not a lot of reasons to avoid caffeine. I mean, there are a lot of health benefits to drinking coffee and tea in moderation. Coffee and tea are protective - appear to be protective against several kinds of cancer, Parkinson's disease, cardiovascular disease. There's been a suspicion that coffee must be terrible for you. From the very start, in the 1600s, they claimed that it reduced male potency. And...

GROSS: (Laughter).

POLLAN: But it's been cleared of that, too. So there isn't a good reason not to drink it unless you have a problem with it - it makes you jittery, or, you know, your doctors told you not to. So I fully intended to get back on it. And I looked forward to the day, and I planned it very carefully. Initially, I thought I'd go to the original Peet's, and that would have a kind of poetic logic to it, but it's a little strong for me.

So my wife and I, Judith, we went to this local cafe where we used to go every morning before I had my fast, and I got my coffee and sat outside. It was a Saturday morning, and it was kind of a beautiful day. And there were lots of dads with little kids, you know, eating pastries. And I had this cup of coffee, and it was mind-blowingly good.

GROSS: (Laughter).

POLLAN: I just - I - you know, I just had this sense of well-being suffusing my body that, you know, rose to the level of euphoria. And I was like, wow. And it seemed like I had taken some kind of illicit drug, that this was cocaine or something. And that lasted for maybe 20 minutes, and then I got a little jittery and a little tetchy. And there was a garbage truck that was, you know, violently shaking these garbage cans into it across the street, and I was like, let's get home. I have to - I want to get some stuff done.

And I felt this incredible surge of almost compulsive desire to get to some - get some stuff done. And I sat down at my computer, and I unsubscribed from about hundred listservs that were really bugging me (laughter) that - you know, these things come up on your computer every day, and you never have time to deal with them. Well, I dealt with them. And then I turned to my closet, and I saw that the pile of sweaters was all scrumbled (ph), and I organized all my sweaters. And I was incredibly productive for a couple hours.

Anyway, the experience made me realize that getting back on coffee and tea is very different than having your maintenance dose. And so I thought, is there a way I could hold on to the power of this drug experience? Otherwise, I was going to slip back into the ranks of, you know, normal caffeine addicts. So for a long time, I said, all right, just have coffee on Saturdays. And for a long time, I did that, and it worked pretty well. And I looked forward to Saturdays. I got a ton of stuff done. But eventually, the slippery slope intervened.

GROSS: So what is caffeine doing for you now?

POLLAN: What caffeine is doing for me now is kind of organizing the rhythms of my day. I mean, something, you know, I missed when I was off caffeine is there is that - you know, that morning surge and that sitting down to work and having that kind of real focus as you attack whatever you're doing for the day. And then even - I enjoyed even the subsiding after lunch and that lull that you got around 3 o'clock, and you could have a cup of tea and that would kind of restore your energy for another hour or two. It just - the rhythm of the day was shaped by ingestion of this molecule. And it's doing that for me now, and I understand that rhythm, and I can - you know, I thread my work through that rhythm, and it works for me. And I did miss it. You know, would I do another fast? I might. I mean, it - you know, I have to say that the pleasure of breaking that fast (laughter) was so great that it's almost worth the work.

GROSS: So some people say, in comparing coffee and tea, that coffee is such an upper that it gets you to lose focus, whereas tea gets you to increase focus. What do you think?

POLLAN: I think it all depends on how you kind of titrate it. When I have a cup of coffee by my side and I'm writing, I don't take a bunch of sips because you can get - you're right; you can kind of overrun yourself, outstrip your mind and get a little too forward, get ahead of yourself. So I think though that we kind of automatically do that. I mean, if you look at when people take a sip of coffee, something's going on. It's not just that they're thirsty. They're reaching - you know, there's some rhythm of the experience that they're modulating, and we do this subconsciously. I think you can do the same with coffee or tea. I don't think it's inherent. But for me, writing, sipping coffee is, you know, really helpful. I didn't feel the same when I was doing that, certainly with herbal tea. You know, I say in the book, what masterpiece has ever been produced on chamomile tea?

(LAUGHTER)

POLLAN: But, you know, green tea is pretty good, too. I mean, it's much more low-level. So I just think whatever the drink, we kind of find a sweet spot for how caffeinated we want to be for whatever we're doing, and you can make those adjustments whether you're drinking coffee or tea.

GROSS: Well, let's take a short break here, and then we'll talk some more. My guest is Michael Pollan, and his new book is called "Caffeine: How Coffee And Tea Created The Modern World." And it's not a print book; it's an audiobook. It's an Audible Original. We'll be right back after a break. This is FRESH AIR.

(SOUNDBITE OF AMY RIGBY'S "PLAYING PITTSBURGH")

GROSS: This is FRESH AIR. Let's get back to the interview I recorded in February with Michael Pollan about his new audiobook "Caffeine."

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GROSS: OK, so enough about coffee for right now. Tell us what's happening with psychedelics. Are...

(LAUGHTER)

GROSS: Are you still - and I should explain for anyone tuning in. My guest is Michael Pollan, and his new book is about caffeine, but his previous book was about the history of psychedelic drugs and new ways that they're being used in scientific research, including working with the terminally ill, to help them kind of reconcile impending death. So I'm wondering if you're still, you know, using them for personal benefit or research purposes, however you'd want to describe it.

POLLAN: Yeah. So I'm following the field closely. I'm not using them now. You know, I became so - I was so public about what is...

GROSS: Yeah, you were. I know.

POLLAN: ...You know, a crime. And so that I'm very careful not to right now since I've told the world that, you know, I did use them. And it was about the book project. If they were legal now, I think I would use them. I think - I can easily imagine every year on my birthday having a psychedelic experience. I think it'd be a great way to kind of take stock of where you are in your life and what you want to accomplish and whatever problems you're dealing with. I think it would be a really useful ritual. But sadly, you know, not yet.

A lot has happened since I published "How To Change Your Mind." The research has been - is really taking off. There are several trials giving psilocybin to depressed patients, both in Europe and here. There's work getting started on eating disorders, which is very exciting. It's the hardest psychiatric condition to treat. There's basic science going on, you know, trying to figure out what - how psychedelics work in the mind. And a lot of really smart scientists are now devoting themselves to psychedelic research. And so I'm very excited about that.

Meanwhile, we're moving to approval. The FDA is supervising these trials of psilocybin for depression and for alcoholism, and there are trials of MDMA, or ecstasy, for post-traumatic stress. And within a few years, it's very likely that both those substances will be medicines that a doctor could prescribe, and that's quite remarkable. It's moving along faster than I would have guessed.

GROSS: I also would like to know what your latest diet is.

POLLAN: (Laughter).

GROSS: And I don't mean weight loss diet, for our listeners who aren't familiar with Michael Pollan. I mean, are you eating meat, fish?

POLLAN: Right now I'm eating an almost exclusively plant-based diet. I am not eating meat at the moment. I'm eating a little bit of fish. But I say this not because I'm urging people to do the same thing. I don't want to be normative about it. It just sort of suits me right now. And I'm, you know, very concerned about climate change. And I've learned from my research in the food industry that one of the most important things you can do to reduce your personal carbon footprint is to cut down on your meat consumption. Beef in particular contribute mightily to climate change.

And so, you know, there are only so many things we can do in our lives. We can, you know, think about the kind of car we drive or, you know, how we heat our house. But our eating is the biggest thing we can do, so I'm trying to eat conscious of that - you know, that goal. And it's been an interesting journey because, you know, I'm learning to cook in a new way and finding that, you know, I really enjoy it. There's the occasional craving. I haven't had a steak in a very long time. And maybe that first steak (laughter) after that fast will be as profound as that first cup of coffee. So, you know, I'm still following my seven-word haiku, you know - eat food, not too much, mostly plants. But the mostly has gotten more extreme than it was when I thought up that slogan.

GROSS: And do you miss what you've given up?

POLLAN: Not as much as I thought. You know, if I were - you know, if I were - no, I actually don't. Every now and then, you know, I'll look over at someone I'm eating with, at their plate and wonder what that - you know, somebody was - I was eating with somebody, and they were having duck the other day, and it looked really good. But basically, you know, I do love vegetables, so I'm happy to eat this way for now.

GROSS: Do you ever - have you ever eaten insects for protein? And would you ever do that?

POLLAN: I have. You know, in Mexico, on tacos, they have, you know, crispy little crickets or whatever it is. And then I was at some - I've been at some high-end restaurants that serve ants and things like that. And a lot of people think that this is going to be an important source of protein going forward. I don't know. We have very strong, you know, disgust reflexes when it comes to insects. I think that goes pretty deep. I know there are cultures that enjoy them.

My suggestion for insects as a protein source is we should grow them. We should farm them and feed them to animals, like chickens and fish, who really like to eat bugs, and then we eat the chicken and the fish. So that's how I think that they should enter the food chain. And I think that they will. I mean, it - by learning how to raise insects in great numbers, we can have much more sustainable aquaculture - for example, fish farming. So I would rather have the animals I eat eat the insects than eat them directly.

GROSS: That makes so much sense. Is anybody trying that?

POLLAN: (Laughter) Thank you. I ran into a farmer in Milwaukee who was doing this indoor aquaculture and he had figured out a way to grow soldier fly larva on compost that he was taking from the city, and then he would feed his fish that. It made for a very sustainable system. This was kind of small scale. I don't know that anyone's doing it on a large scale. But I think it makes a lot of sense. You know, a lot of the problem with meat production is the food source and that that is so unsustainable, all the corn and soybeans we have to give them. And so if you can get the fish and the chickens off of those crops - which are produced in a very environmentally unsustainable way - and get them to eat bugs, everybody wins.

GROSS: Michael Pollan, great to have you back on FRESH AIR. Thank you so much.

POLLAN: Always a pleasure, Terry. Thanks a lot.

GROSS: Michael Pollan's new audiobook is called "Caffeine: How Coffee And Tea Created The Modern World." It's an Audible Original. Our interview was recorded in February. After we take a short break, jazz critic Kevin Whitehead will review a new album by guitarist Jeff Parker that Kevin describes as genre-bridging. This is FRESH AIR.

(SOUNDBITE OF ALLISON MILLER'S "SHIMMER") Transcript provided by NPR, Copyright NPR.