Caffeine: The World’s Most Popular Drug

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How are you in the morning before you have your coffee?

The most charming man in the universe.

I thought we said this was a terrible day to record me.

Isn't any day before you have your coffee in the morning?

Yes, yes.

How much do you like caffeine?

I don't like that I don't have it, that I'm talking to you instead of preparing it.

Oh, that smells so good.

That's it.

Now I stand in the middle of the kitchen for another 48 seconds, trying not to fall asleep.

And you'll be a lot more pleasant in a little while once you've actually had some coffee.

Are you implying on international podcasts that I'm unpleasant right now?

I actually didn't even dare record Jeff before his coffee.

You're a brave woman, Cynthia.

Things I'm willing to risk for Gastropod, like my relationship.

Sorry, Tim?

Yes, today we are talking about the most important thing of all.

It's not love, it's caffeine.

This is Gastropod, the podcast that looks at food through the lens of science and history.

I'm Cynthia Graeber.

And I'm Nicola Twilley, and today's episode was inspired by a listener question.

Hi, my name is Eric Vance and the other day I actually went into a tea shop to pick up some green tea because I wanted some caffeine-free tea and the guy there told me actually green tea has caffeine in it and sometimes more than black tea, which is really confusing because I had been in another tea shop where they said the opposite.

And so I would like you to do a show about how much caffeine is actually in different things that I drink, like like coffee, like black tea, like green tea, like

mate, like all these other different things, because I feel like no one can agree.

We are going to get Eric his answer, and so much more besides.

But first, we have something to ask.

You may think that Nikki and I just sit down and joke around, and the next thing you know, an hour later, there's a podcast for you.

I wish that were true.

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So, let's cut to the chase.

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Caffeine in its purest form, you know, the essence of caffeine, it's a bitter white powder.

It looks like cocaine.

That's Murray Carpenter.

He wrote a book all about our favorite white powder called Caffeinated, How Our Daily Habit Helps, Hurts, and Hooks Us.

Before we can answer Eric's question, we figured we needed to get to know caffeine a little better.

Bennett Alan Weinberg is co-author of the book The World of Caffeine.

Caffeine is used around the world.

It's used by over 90% of the people in the world on a very regular basis.

It is the most popular indulgence in the world, more popular than rock music, than even than sex, than alcohol, than tobacco, and all these things put together.

It is the most popular drug in the world.

But as Murray pointed out, it is hard to think of caffeine as a drug.

Just because we're all taking it every day, we just want to think of it as, you know, coffee or tea.

And like all drugs, it does some interesting things to your brain.

Basically, what caffeine does, it blocks a neurotransmitter that's telling your brain that you're tired, adenosine.

And it's a simple trick and it works.

It works beautifully.

The caffeine molecule, basically, it looks enough like adenosine that it can lodge in the receptors for adenosine.

It sort of nudges adenosine away from its stool at the bar.

So because your brain isn't getting the signal that says, hey, I'm tired, you feel peppy and alert.

I think the simplest way to say it is it just, especially if you're a habitual caffeine user, habitual coffee drinker, habitual tea drinker, it just makes you feel good.

Caffeine is a chemical that's naturally made by plants.

Lots of different plants have evolved the ability to do it on lots of different continents.

But obviously, caffeine didn't evolve to make humans feel good.

No, plants didn't have us in mind.

For decades, scientists thought that plants evolved caffeine as an insecticide.

Food science expert Harold McGee says recent research shows it might be a little more complicated.

It has long been thought that caffeine is there in such large quantities to deter predators of various kinds because caffeine is a compound that acts on the nervous system of animals and

in large quantities can screw up those nervous systems.

And so it was thought that that was the purpose.

It was a deterrent.

But I just have been looking the last couple of days at the current literature on the role of caffeine in the biological world, and it seems to be much less clear.

So a lot of insects apparently don't mind caffeine.

And in fact, in some cases, it appears that in small doses in flowers, it actually does for bees what it does for us, which is helps them pay attention to what's going on and do a better job at whatever they're doing.

And so, you know, maybe it's a compound that's active against certain kinds of animals and not others.

And maybe some animals have adapted to it or found uses for it.

Anyway, it's a much more interesting question now than it was 10 years ago.

So how did humans first discover that this plant chemical had some rather pleasing side benefits?

Murray traveled to Central America, the place where humans have been using caffeine for the longest.

The oldest use of caffeine for which we have like physical evidence comes from Mesoamerica, what would be now the border of Mexico and Guatemala on the Pacific coast.

And in this area, people were already using cacao, you know, chocolate, more than 3,000 years ago.

I did visit this region and it's really interesting because they still have cacao groves.

It was a basis of their economy back then and it still is now.

And back then they weren't eating chocolate the way we do now.

It certainly wasn't sweetened and it wasn't in a bar form.

They were having these like frothy.

chocolatey drinks.

We don't think of chocolate as being super caffeinated, but the stuff we eat today is somewhat different from chocolate treats 3,000 years ago.

Yeah, well, there's a couple of reasons we don't think of chocolate as having much of a buzz.

I think the biggest reason is that most of the chocolate we consume as chocolate really just doesn't have much cacao in in it, the seed that gives us chocolate.

We consume chocolate in this country in a very dilute form.

So, you know, a Hershey's bar, for example, has a very small percentage, maybe 11% cacao.

Now, increasingly in recent years, we've all seen these, you know, expensive but really tasty 70% cacao sort of gourmet chocolate bars.

Those really do have, you know, significantly more caffeine.

And

say, a half of a gourmet dark chocolate bar would easily give you the same dose of caffeine as, say, a cup of tea.

So, you know, not super caffeinated, but definitely caffeinated.

Another reason to eat the good stuff.

Thanks, Murray.

Chocolate is the first, as far as we know, though there are myths that have people drinking tea that far back.

Recently, archaeologists found tea leaves buried with a Chinese emperor that are 2100 years old.

Getting close.

And tea is the most popular drink in the world.

Bennett told us it's second only to water.

And of course, tea originally comes from Asia.

We think that it might might have started in northern India, and then very early on came to China, and then from China to Japan, and then around the world from there.

Tea's origins are shrouded in myth, but coffee?

That is actually a full-blown mystery.

The story, the one you might have heard, is that an Ethiopian goatherder saw his goats dancing around on their hind legs, going all kinds of crazy after nibbling on these bright red berries.

That is undoubtedly apocryphal.

And in any case, the reality is much more bizarre.

It's quite fascinating, in my opinion, and no one has ever really solved it.

Around 1500, a little bit after 1500, coffee was grown in the Yemen, and the first coffee shops, cafes, we might call them today, opened up in the Yemen.

They quickly spread from there to Egypt and then around the Middle East and then around the world.

Arab historians writing at the time were clear that they hadn't heard of coffee before.

They didn't have any stimulant like it.

In other words, it was strange because it sort of appeared around 1511

and nobody knew where it came from.

Now, the mystery really deepens when you consider that coffee grows wild all over Africa.

And the ancient Greeks, for example, were familiar with the African tribes all the way down through Nubia.

And the Egyptians were obviously familiar with the African tribes in northern Africa.

The Phoenicians sailed around Africa.

None of these cultures, Greeks, Egyptians, Phoenicians, or anybody else, ever mentions or knew about coffee.

Why that could be or how that could be is really unknown.

So Greeks, Romans, Arabs, everyone knew Africans, and coffee grows wild in Africa, but nobody had heard of coffee until 1500.

So we just don't know the coffee origin story, really.

But historians think that people would have started out just eating the coffee berries.

And then, once they realized this stuff was good, they wanted to trade it over distances.

And that meant drying it and roasting it.

And that meant coffee, more or less as we know it today.

Harold says the same deal was true for tea.

Because caffeine dissolves in water, you can dry coffee beans and tea leaves and then get at the caffeine by soaking them.

People have probably been chewing the leaves initially to get the benefits of caffeine, and then tea was developed developed as a way of preserving those leaves for use and for trade over long distances.

So we know that caffeine peps you up, and thanks to Murray, we know it does that by blocking your fatigue receptors.

But how quickly does it work?

That was another question we had for Harold.

The absorption takes place over a couple of hours, and so you end up with the highest levels in your blood, not immediately after drinking, but some hours after drinking.

But of course you will begin to feel the effects as the levels in your blood rise.

And I think most of us can testify to that from personal experience.

And then it lasts for a few hours.

So the blood levels reach a maximum couple of hours after you've drunk the coffee or tea, and then it slowly declines over the course of hours.

You all know the feeling.

Suddenly you pep up, you're alert, you can focus.

This was a revelation when it hit Europe in the 1600s.

Europe is one of the few continents, along with Australia and obviously Antarctica, that doesn't have a native caffeinated plant of its own.

They only had downers like boobs, which people were drinking plenty of.

So when coffee and tea started to be widely available in Europe in the 1700s, it blew people's minds.

In fact, Stephen Johnson gives it credit for fueling the scientific enlightenment.

It's in his book, The Invention of Air.

He spoke about it in a book talk he gave in the Bay Area.

Because until coffee and tea became kind of mainstream beverages in the 18th century, the daytime beverage of choice for both the mass and elites in British society was alcohol.

And so it's not an accident.

I mean, it sounds like a joke.

It sounds like something somebody who drinks a lot of coffee would say.

But it's not an accident that the age of reason accompanies the rise of caffeinated beverages.

The beer they were drinking was pretty low alcohol.

But even so, if you start drinking coffee instead, you're going to be sharper, you're going to be more productive.

The culture is moving from a depressant to a stimulant.

And so the places where people came together to drink caffeine became intellectual powerhouses.

The coffeehouse was a great hub of Enlightenment era culture.

People would come into the coffeehouse, they would hang out, they would share ideas, they would come from different disciplines.

A whole number of crucial events in the history of Enlightenment culture have a coffeehouse somewhere in them, one way or another.

The whole insurance business is invented in Lloyd's coffeehouse, which becomes Lloyd's of London.

Arguably, we have coffeehouse culture to thank for the U.S.

Constitution.

Those political ideals came out of caffeinated conversations, Bennett told us.

Places where people drank coffee became a meeting point where revolutionaries and writers and artists and scientists gathered to talk.

Caffeine was inspirational.

For example, when coffee first came to England, it arrived in Oxford, and scholars like Christopher Wren and Isaac Newton discovered it and they realized they could think more clearly when they drank coffee.

At the time there weren't coffee houses, so they convinced a pharmacist to serve it to them.

Then they'd all sit around and get their buzz on and talk about literature and science.

They dissected a dolphin dolphin on the table.

They did all kinds of things and they called it the Oxford Coffee Club.

After a few years, the Oxford Coffee Club moved to London and they got a charter from the king to create the Royal Society.

The Oxford Coffee Club was the antecedent of the Royal Society, which still exists today, one of the greatest scientific societies in the world.

Coffee was such a shock to the European system that almost every country tried to ban caffeinated drinks at one time or another.

Charles Charles II tried to ban coffee at the end of the 17th century and it was so popular that he couldn't do it.

He put a ban in and then revoked it immediately because it was about to create almost a revolution.

People were enjoying coffee and they weren't about to stop using it.

So even the king couldn't stop them.

Political revolution, new business models, dissected dolphins, all thanks to caffeine.

It's powerful stuff.

But it doesn't just affect your brain.

Murray told us that it gives athletes a boost.

If I were to go out and run for an hour today without caffeine and then do the same thing tomorrow, I would go like between 1% and 3% further tomorrow

than today.

Or I would reduce my time on, say, a measured course by between 1 and 3%.

So it's significant.

It's often the winning margin in a race.

And so athletes are really definitely using caffeine to boost their performance.

And not just because they can focus focus better and they don't feel tired.

There is some research that suggests that every contraction, every muscular contraction is slightly more forceful with caffeine than without, particularly in the big muscles of the leg.

The way they figured this out is kind of funny.

Basically, a Canadian scientist strapped people down and gave them electric shocks so that their muscles were contracting without their brain being involved at all.

And the caffeinated people had stronger muscle contractions from the same shock.

The leading theory is it's something to do with caffeine making more calcium available to your muscle, although we really don't know why it works.

But talk about suffering for science.

Murray explained that coaches and trainers have worked out how and when athletes should use caffeine gels to get the best boost, and this is one popular drug that isn't considered doping.

Also, a side note, caffeine does not make you dehydrated, despite the fact that you've probably heard this.

You won't pee when you drink coffee any more than you do from drinking water.

So you're less tired, you're more focused, and your muscles work better too.

Is there no limit to caffeine's wonders?

We asked Murray what he thought about recent studies that seem to show that if you drink coffee, your heart will be healthier.

Is there any significance there?

Well, I think plenty of significance, especially if you love to drink coffee.

No, I think there is some really good research that suggests that long-term coffee drinking, moderate to even heavy coffee drinking, is not only not associated with an increased incidence of cardiac disease, but maybe a lower incidence of cardiac disease.

So I think there's something there, and

it's really hard to know exactly what the mechanism is.

And these studies are done by measuring coffee consumption rather than pure caffeine.

So it's hard to tease out whether the protective effect could be to do with other chemicals in the coffee, of which there are many thousand.

Same with tea.

There seem to be lots of great health benefits, but we don't know if that has anything to do with the caffeine itself.

Still, I'm happy to keep drinking my cups of tea.

But, but, but, caffeine is not all sunshine and bulging muscles.

It can cause insomnia, and it can make panic attacks more likely for people who suffer from anxiety.

And as you heard my partner Tim grumble, once you're used to getting that shot of energy in the morning, it's hard to give it up.

One of my sources, I think, put it best by calling it mildly addictive.

Because once you are a habitual caffeine user and you have a caffeine habit, you are definitely going to feel lousy if you don't take it.

And if you skip, you know, 24 hours, 36 hours without caffeine, you might start to feel some withdrawal symptoms.

And that could be headache, sort of even flu-like symptoms for some people.

Another interesting thing about caffeine is we develop a partial tolerance to it.

So the first cup of coffee you ever had is going to hit you harder than the cup of coffee you have daily if you're a habitual user.

This tolerance thing is interesting.

What happens is you drink your daily coffee or tea or whatever, and the caffeine blocks your adenosine receptors.

So, your brain makes more receptors.

And so, then that same amount of caffeine doesn't have quite the same effect.

And it's possible, and this is my theory anyway, for what it's worth, that caffeine withdrawal is just how you feel when you have all of these extra receptors and nothing blocking them.

But that sluggish flu-like feeling goes away after a couple of days, and then if you stay caffeine-free, you hit the reset button.

So, even if you're a moderate to heavy caffeine user, such as myself, if you go cold turkey for a week to 10 days, you'll probably get back to a baseline where your tolerance is either gone or dramatically reduced.

And yes, probably a lot of that has to do with how many adenosine receptors you have.

And this is an area of research that people are learning more about all the time.

But a little headache or not being able to sleep, that's not the worst caffeine can do.

It is lethally toxic at the right dose.

A tablespoon, like one heaping tablespoon, would reliably kill an adult.

So that's about 10 grams.

To put that in context, Murray said that a good solid cup of coffee would only have about 1/16th of a teaspoon.

A tablespoon is about 48 times that.

That fourth cup of coffee is not going to do it.

You'd actually have to be downing the purified powdered stuff to kill yourself.

Unfortunately, that's exactly what a few people have done, including this one guy Murray told us about.

Yeah,

this was a guy who was at a party in England.

You know, he had bought caffeine powder off the internet, and he washed down a couple of spoonfuls with an energy drink and

immediately went into seizures and had heart trouble and died.

Luckily, nearly all of us enjoy this drug safely every day.

But there are some really interesting variations, kind of dramatic variations, in how much caffeine is in different drinks and how our bodies deal with it.

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You know that point in the afternoon when you just hit a wall?

You don't have time for self-care rituals or getting some fresh air, so maybe you grab a beverage to bring you back.

But somehow it doesn't do the trick, or it leaves you feeling even worse.

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Time for a tea break, time for a Pure Leaf.

So as I mentioned, my caffeine regime, not that I'm the sharpest, most optimized individual in the world, but still.

I have two cups of strong British tea in the morning, and if my husband's around to make it, I'll have a coffee too.

And then, if things get rough, and if the weather is right, the afternoon might call for an iced coffee.

And then, long drives, well, that requires Diet Coke.

I couldn't possibly handle all that.

I actually can't drink caffeinated coffee.

It gives me horrible, horrible stomachaches.

So, I've become something of a tea addict.

But usually I only drink one large cup in the morning, either black or green tea, and then I steep the same leaves a few times more.

Sometimes I'll have a fresh cup in the afternoon, you know, if it's a really bad day.

So I think it's pretty clear that I'm getting more caffeine than you, Cynthia.

But to get back to Eric's question, how do all these different caffeination options compare?

Black tea versus green tea, coffee versus Diet Coke?

Like most things we cover on Gastropod, it is much more complicated than we'd like it to be.

Sorry, Eric.

For tea drinkers and for coffee drinkers, and for people who get their caffeine through chocolate, although it's fewer of us that do that.

One of the complicating factors here is that tea and coffee are natural products, and they might vary dramatically from coffee bean to coffee bean and tea leaf to tea leaf.

It's a plant.

This kind of natural variation, it's not surprising when you think about it.

Add on to that the brewing strength.

Some people like a very strong, longer steep in their tea bag.

As we explained, caffeine dissolves in water.

So the longer you steep, the more caffeine you get.

With coffee, some people like say less water and more coffee, you know, a higher ratio of coffee beans to water.

You get a tremendous amount of variation from cup to cup.

It is a complicated thing, and it's very difficult for consumers to figure out how much caffeine they're getting in their coffee or tea.

Since we started reporting this episode, I've noticed that I use significantly more loose green tea than black for my morning mug.

So I'm probably getting just as much caffeine, even though green tea usually has less than black ounce for ounce.

You might also be surprised to learn that tea leaves actually have more caffeine in them than coffee beans.

But we use a lot more beans to make a cup of coffee than we do leaves to make a cup of tea.

So in the end, you'll usually get more caffeine from coffee than tea.

But the plant's natural variation and your brewing strength, those are not the only variables.

Take the roast for coffee.

That makes a difference too.

I think we associate the richer, kind of darker flavor of a dark roasted coffee with a stronger caffeinated kick.

Lightly roasted coffees, actually, bean for bean, have a little bit more caffeine than a dark roasted coffee.

I mean, some of the caffeine is actually being roasted off in the process.

And the other thing that's counterintuitive is the cheaper, robusta beans have more caffeine than the fancy Arabica ones.

And then when you talk about sort of the less expensive commercial coffees, Folger's, Maxwell House.

They're often blended with a combination of Arabica beans, and these are the mountain-grown beans that most of us love, the sort of gourmet coffee.

They're also blended with Robusta beans, which are they're easier to grow.

They're a less expensive, less tasty bean, but much more caffeinated.

So yeah, if you really want a caffeinated kick, a light roasted commercial coffee might be the way to go.

There's more.

There's the particle size.

Are the tea leaves ground up or whole?

Is the coffee a fine grind or a coarse one?

There's the temperature of your water.

Hotter water gets caffeine out faster.

So does pressure, like in an espresso machine?

Basically, the result is chaos.

There's this crazy study that a scientist named Bruce Goldberger did.

He's a forensic toxicologist at the University of Florida, and Murray interviewed him for his book.

He did a really interesting experiment, which is he went into the same Starbucks and ordered the same coffee, the same 16-ounce, the grande size, from the same store, I think six days in a row.

And then measured the caffeine content in the coffee.

And one day, I believe it was as low as 250 milligrams.

Another day, it was as high as 560 milligrams.

So it's not only varying more than twofold, the same coffee from the same store on different days.

But when you're up at the high end, 560 milligrams, I mean,

that's a lot of caffeine.

That's as much as seven Red Bulls from one cup of coffee.

Wow.

So, yeah,

there's tremendous variation from cup to cup.

And that's just the drinks.

Sad to say, the variability continues when it comes to how we metabolize the caffeine in those drinks.

Some of this is genetic.

You know, some families, you find people who are just generally not very susceptible to caffeine.

These are the kind of people who drink coffee right up until the moment they go to sleep and sleep like babies.

Humanity is split about half and half.

50% carry the genetic variation to metabolize caffeine slowly, so it stays in their body longer and affects them more.

The other 50% have the fast metabolism variation.

We are split 50-50 here on Gastropod, too.

I am definitely fast.

I can chug six espresso and take a nap.

I can't even imagine that.

I am super sensitive to caffeine.

I accidentally drank black tea that was pumped with an extra dose to make it more like coffee, and I was super jittery and nauseous, and I could not wait for the feeling to go away.

And it's not just my genes, there's more.

When you factor in, say, weight, you know, a big person is going to to need more caffeine to get the same dose as a small person, you can get remarkable differences in how people are metabolizing caffeine.

Put another way, you know,

what's a reasonable dose for one person might just send another one to the moon.

Age is a factor, too.

The older you get, the slower your caffeine metabolism gets, typically.

You get further along the Cynthia end of the spectrum.

That's our body's natural individuality.

But then there are things we can do that affect how we metabolize caffeine.

One of them is smoking cigarettes.

And smokers metabolize caffeine more quickly than the rest of us.

So they burn through caffeine just quicker than non-smokers and significantly.

So a smoker might have to have two cups of coffee to have the same effect as a non-smoker.

And women on birth control pills, by contrast, metabolize caffeine more slowly, almost twice as slowly as people who wouldn't be on birth control pills.

Murray calls this the madman versus sex in the city effect.

Take a man who's maybe 180 pounds, a woman who's, say, 120 pounds.

He's a smoker, she's a non-smoker, she's on birth control pills.

All else being equal, he would probably need six cups of coffee to equal her one.

Hence, why Don Draper chugs coffee all day long and Carrie Bradshaw does not.

And on top of all that, different foods we eat can affect caffeine too.

Bennett says that, according to some studies, grilled meats and broccoli can speed up your caffeine metabolism, so you'd have to drink more to get the same effect.

And on the other hand, grapefruit can slow down your caffeine metabolism by a third, buying you an extra 40 minutes of buzz.

This might, might help explain the popularity of a new caffeinated beverage that's kind of weirdly become all the rage.

Bulletproof coffee is the idea of taking just regular coffee and adding grass-fed butter to it and sometimes other types of oils, but it's basically a buttery coffee drink, more or less.

Jenna Wertham is a staff writer at the New York Times magazine, and she wrote an article all about self-optimization and biohacking.

And as part of that, she looked into this quote-unquote new and improved coffee, and she met the guy who, quote-unquote, invented it.

Dave Esprey is like a pretty interesting guy.

He has a long history as an entrepreneur in Silicon Valley and started a couple of cloud computing companies and

came up with the idea, or I guess he just, you know, came across the idea, I should say, when he was traveling through the himalayas and he came across um tibetan people who were who were adding yak butter to their tea this is totally normal and traditional in the himalayas my best friend from school is tibetan and she has fed me more butter tea than i like to remember the reason he was so interested in it is because he was you know like most of us experiencing the kind of midday

um crash that you get and then drinking coffee and then you kind of spike and get a ton of energy and then crashes again and he was looking for something to help him balance out his energy levels and moods and if it turned out that this yak butter tea did that for him.

Dave Asprey preferred coffee to tea so he added butter to that instead and then he did what any Silicon Valley entrepreneur would do.

He packaged the whole thing for sale as bulletproof coffee.

Well the idea around it is that the fat and the butter helps you absorb the caffeine more efficiently and it kind of keeps you from having that crazy rush of energy and then the tapering off around 3 p.m.

where you have to go get like another giant latte with two shots.

We wanted a quick back check here, so we turned to our favorite food and science guru, Harold McGee.

What I imagine might be going on, if it turns out to be that that's true,

then my rationalization of that would be that fats and oils simply slow the process of absorption of caffeine and other things from the stomach.

So it would make the rise of the caffeine levels in your blood gentler over a longer period of time.

That's, I think, what could be going on.

I can't come up with any other scenario that would explain that kind of effect.

Jenna's a sample size of one, but when she tried it, she had quite a response.

I felt completely insane.

I mean,

I like caffeine and I'm definitely a high-energy person, but it made me feel mildly high, which I guess is a good thing.

But I definitely felt the crazy rush and I had a ton of energy and it did last for hours.

I mean, that was the nice thing.

I definitely felt really satisfied, but I couldn't get over the fact that I was drinking kind of a big cup of butter, you know, like it felt, I don't know, I couldn't get my head around that fact.

But there is no proven science here at all.

Who knows?

It could be true.

It's possible that fat could be like grapefruit and slow down caffeine metabolism, but those studies have not been done.

And even if it was true, I don't think it would convince me to put a load of butter in my tea, personally.

I mean, they need all those extra calories in the mountains of Tibet.

I mean, there are a lot of people that push back on his claims and a lot of people that don't buy into it.

And it's like anything in the wellness economy, right?

Like somehow it might work for certain people.

It might not work for other people.

A lot of it is sort of

buttressed by half-assed claims.

So hard to, it's, that was the takeaway.

That was my ultimate takeaway from that piece, which is that all this stuff is sort of placebo effect.

Sorry to burst the bulletproof bubble, folks.

Another surprising thing we learned when we were making this episode is that despite the rise of high-end coffee shops and specialty roasters and bulletproof coffee, we're actually drinking much less of the stuff than our grandparents did.

They drank about twice as much coffee as we do.

You know, coffee consumption peaked in this country probably around 1950 and then declined somewhat precipitously.

And the big change in that same time is that we've really started to consume a lot more soft drinks.

And the reason that belongs in this conversation is that all the most popular soft drinks are caffeinated.

All of the top six soft drinks in this country are caffeinated and eight of the top 10.

So we've really shifted our dietary preferences from one form of caffeine to another.

You know, a lot of people are drinking both.

A lot of people are drinking coffee in the morning, soft drinks in the afternoon.

But it's a pretty profound dietary shift.

What that also means is that a large part of the caffeine we consume now is synthetic.

It's not from a plant.

It's from a factory.

And that factory is more than likely in China.

Murray tried to visit the largest caffeine factory in the world, but he couldn't get inside.

But what he saw from the outside was more than enough to make me rethink my Diet Coke habit.

It was really a run-down industrial park, and there was a central steam plant and then pipes winding over the road to all of these different factories, some of which produce amino acids, some of which produce vitamins.

One of them was just absolutely run down and

abandoned and sort of leaking tarry substances from tanks.

And this right down the street there was the largest caffeine plant in the world.

And it's producing synthetic caffeine for Coke and Pepsi and other large bottlers.

So

I was really surprised at what I saw.

Murray pointed out that European and American governmental agencies have a hard time getting inside to inspect this caffeine factory.

Companies like Pepsi and Coke usually do their own private inspections.

But you were serious, Nikki, right, about cutting out the synthetics?

Yeah, even on a road trip out west last week, where I would normally always get a Diet Coke when I stop off for gas, I didn't.

I was just really put off by the idea of drinking this stuff based on what I know about safety standards in Chinese factories.

It was hard, but it's not like that stuff is good for you anyway.

But look, Eric had an urgent question for us.

His afternoon depends on it, and we can't fail him.

What drinks of more caffeine?

Harold gave us some answers.

Generally speaking, coffee is going to have more than tea.

Generally speaking, brewed coffee is going to have more than espresso because espresso comes in such a small volume, even though you're extracting more efficiently.

If you really want to have just a little bit of caffeine, or at least a little bit more control, Harold suggests going with DIY tea.

You know, just order a cup of water and a tea bag and just dip it in for as long as,

as little time as gives you something that you're willing to drink.

Then you're controlling the infusion.

You're controlling how much time the caffeine has to come out of the tea.

And you can choose to make that as much or as little as you like.

Yes, in general, tea has less caffeine than coffee, and green tea usually has less caffeine than black tea does.

And surprisingly, Murray told us that cola and other regular soft drinks, they often have less caffeine than coffee too.

About the same as tea, actually.

But he didn't have a definitive rule for Eric either I wish I could give you the simplest answer here but you know the easiest way to say this is if he gets the same brand and they've got you know the same amount of grams of tea leaf in the bag then yeah you know probably green is going to have less caffeine than black for sure I mean the research suggests this However, you know, if he gets a brand of green tea that's got sort of a heavier dose of tea in it than the brand of black tea, that's not going to hold true.

And I think, in terms of your desperate listener question, these are the questions that I get all the time.

There's not a really easy answer here.

What I think consumers really need to do is be informed and notice, okay, yeah, you know, I got Lipton tea last time and I got the black tea and I felt good and it seems to work for me.

Or, you know, I got Bigelow green tea that seemed to be good.

Or I had medium roast Colombian coffee and I made a you know moderate brew and that was good.

You just sort of need to minimize the variables and find out what works for you and listen to your body to see what the caffeine makes you feel like and you know what works out well.

So, Eric, to answer your question, yes, green tea does have caffeine, and your cup of it could have as much caffeine as black tea, but it probably doesn't.

We haven't even mentioned your bamate or guarana in South America.

Your bamate seems to have as much in a cup as a small espresso.

At the end of the day, the best answer our experts can give you is to figure out what makes you feel great and drink it.

And what's crazy is, for the most part, that is what we all do.

In the book, Murray says that for most of us, the way we consume our favorite drug, caffeine, it's a stable and orderly form of self-administration.

We don't binge or go cold turkey.

We don't tend to vary very much.

We basically figure out what dose brings us to our happy places and we stick with it.

In studies where people were given a series of drinks and they didn't know exactly how much caffeine was in them, they all ended up ingesting basically the same amount of caffeine as usual.

They just stopped when they were done, whether that took one cup or a bunch.

This was surprising to me.

We're so bad at knowing how many calories we've eaten, for example, just to go back to our earlier episode.

But somehow we know intrinsically how much caffeine we've had.

It's kind of reassuring, however much caffeine you're consuming and in whatever form, you're probably getting the right amount for you.

Unless you're screwing around with spoonfuls of that pure white, potentially toxic, cocaine-like powder, The wisdom of the body will probably not save you there.

But as long as you're sticking with the kind of dose that you'll find in tea, coffee, chocolate, and soda, you're good to go.

If you enjoy it, keep on enjoying it.

Denna and Murray most certainly are.

I love caffeine.

I love coffee particularly.

I've been a daily coffee drinker for, you know, more than 30 years.

I never don't have caffeine.

Harold plays it a little cooler.

I enjoy it, but I don't miss it if I don't get it.

But you know he's still a caffeine lover at heart.

As am I, and I can tell you that I will never again stick a mic in front of Tim before he's had his morning coffee.

Thanks this week to our caffeine experts.

Murray Carpenter is the author of the fascinating book Caffeinated: How Our Daily Habit Helps, Hurts, and Hooks Us.

We wanted to include much more from the book than we could in the show.

You should definitely check it out.

Harold McGee is an expert on food science and the author of the food science encyclopedia called On Food and Cooking.

Bennett Allen Weinberg is co-author with Bonnie Buehler of The World of Caffeine.

They also have a website, Worldof Caffeine.com.

Jenna Wertham is staff writer at the New York Times magazine and author of the article You, Only Better.

Links on our website at gastropod.com.

Thanks to Eric Vance, the listener who sent us down this caffeine rabbit hole.

I always feel like I learned so much when we do the reporting for our episodes, but this one kind of blew me away.

Come back in two weeks where we will be telling shocking tales of almond thefts and syrup heists.

It's like Ocean's 11, but the swag is food.

Till next time.

This month on Explain It to Me, we're talking about all things wellness.

We spend nearly $2 trillion on things that are supposed to make us well.

Collagen smoothies and cold plunges, Pilates classes, and fitness trackers.

But what does it actually mean to be well?

Why do we want that so badly?

And is all this money really making us healthier and happier?

That's this month on Explain It To Me, presented by Pureleaf.