Updated 14th March 2023

Is dark chocolate good for weight loss?

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    This plant has been used by human beings for thousands of years, with samples found in 5,000-year-old pottery discovered in the upper Amazon. The Mayans considered it a gift from the gods and used it in their sacred ceremonies, where it was believed to have mystical healing powers. For the Aztecs, it was worth more than gold and given to their victorious warriors. 

    We are talking, of course, about chocolate. Even though our relationship with chocolate spans thousands of years, we still can’t agree about it. It seems obvious that something so delicious must be bad for us. Can there be any truth to the claims that chocolate can improve our mood, our health, and even our libido? 

    In this podcast, Jonathan Wolf speaks to Professor Tim Spector, one of the world's top 100 most cited scientists and author of The Diet Myth, and Spencer Hyman, one of the world’s leading chocolate experts and founder of the craft chocolate business Cocoa Runners.

    If you want to uncover the right foods for your body, head to joinzoe.com/podcast and get 10% off your personalized nutrition program.


    Jonathan Wolf: [00:00:00] Welcome to ZOE Science and Nutrition, where world-leading scientists explain how their research can improve your health.

    This plant has been used by human beings for thousands of years, with samples found in 5,000-year-old pottery discovered in the upper Amazon. The Mayans considered it a gift from the gods and used it in their sacred ceremonies, where it was believed to have mystical healing powers. For the Aztecs, it was worth more than gold and given to their victorious warriors.

    Today, this plant fills shelves around the world. We gift it to our loved ones to express our feelings or help ourselves through hard times. I'm talking, of course, about chocolate. 

    Even though our relationship with chocolate spans thousands of years, we still can't agree about it. It seems obvious that something so delicious must be bad for us.

    Can there be any truth to the claims that chocolate can improve our mood, our health, and even our libido? [00:01:00] Well, today, we looked at the latest science to find out. I'm joined by Tim Spector, my scientific co-founder at ZOE and one of the top 100 most cited scientists in the world, and Spencer Hyman, one of the world's leading chocolate experts and founder of the craft chocolate business Cocoa Runners. 

    Wonderful to have you both. So, just to kick off, I thought we'd try and do something different, which we haven't done before because there's a lot of myths and stories about chocolate. And so I thought we could try and hit a whole bunch of them very fast with a lightning round of true or false answers.

    And if you'll just each answer to that, and we'll go around, then I kick this off. So first question: chocolate causes acne, true or false.

    Tim Spector: False. 

    Spencer Hyman: False. I've never seen any studies for that. 

    Jonathan Wolf: All right. So Tim and Spencer say no. So next one, chocolate is high in caffeine. 

    Spencer Hyman: False. There is a small trace element. It's theobromine which chocolate has in there.

    Tim Spector: Yes, agreed. 

    Jonathan Wolf: There you go. [00:02:00] So, we already established Spencer's expertise in chocolate. That's good. Dark chocolate is healthier than milk chocolate. 

    Spencer Hyman: I'm going to sit on the fence on that one because it depends on how you do your milk chocolate. There's something called dark milk chocolate, which actually has no added sugar to it. So you actually have less added sugar to that than you can to some dark chocolates. 

    Jonathan Wolf: Fascinating. We will come back to this one for sure.

    Brilliant. And uh, next one, chocolate is bad for your heart.

    Tim Spector: False. 

    Spencer Hyman: Definitely false unless it's got lots of sugar in it, which is another issue. 

    Tim Spector: Depends on the type of chocolate, but, uh, the good chocolates, it's not bad for your heart. 

    Spencer Hyman: We can talk about the Una a bit later, that great tribe of people who sort of have this extraordinary ability to drink like 17 cups of chocolate a day, eat fish, and have amazingly healthy hearts as a consequence, which is what a lot of this stuff sort of comes from. But yeah. 

    Jonathan Wolf: Chocolate causes headaches. 

    Tim Spector: False. 

    Spencer Hyman: There is a small study that shows that one of the things inside chocolate or something called PEA, and there is a [00:03:00] tiny bit of evidence, well, there's a few studies which suggest that for people who can't break down PEA, that may be the case, but it's a real exception. There's only been like two or three studies done on it as a general rule of thumb. Tim is right again.

    Jonathan Wolf: Tim, possibly a personalized response in some people, or you just don't believe it?

    Tim Spector: Well, there's always exceptions to rules, so I'm sure I never say never, but as a general rule, there is a general myth that chocolates cause migraines, and generally, they do not. Studies have disproven that myth. It doesn't mean anyone can't get a headache with any particular food or product, but I don't think there's any general risk of chocolate and migraine and, for example, or really bad headaches. 

    Jonathan Wolf: Got it. So the idea that chocolate, in general, is a problem… 

    Tim Spector: They've done placebo-controlled studies and, uh, there's no difference in those studies to provoke migraines and people who thought they were sensitive to it. So I think it's generally been disproven. 

    Jonathan Wolf: Brilliant. Spencer, good for your [00:04:00] business. 

    Spencer Hyman: Yeah, that is good. It's just literally anybody who can't break down PEA. But as you say, that will happen with lots of other foods, but it is specifically people who have a problem with PEA who do have a problem with chocolate because chocolate has got lots of PEA now.

    Jonathan Wolf: Brilliant. Next question. You can eat as much dark chocolate as you want without worrying about it. 

    Tim Spector: I would say that's not true. You always worry about eating unlimited amounts of anything because you need to have a balanced diet and eat something else as well. So, I mean, Spencer thinks you can live forever on just chocolate, but I think that'd be unlikely.

    Spencer Hyman: You would be right that you need a bit of variety too. Maybe one of the next questions is going to be: Is chocolate addictive? And the side for this is that it's almost impossible for people to actually eat enough chocolate for it to become addictive. So I don't think you can eat too much chocolate, but, um, for it to, for example, to become addictive, you definitely, you would not want to just eat chocolate. That would not be a good idea. A little bit of chocolate has other advantages. 

    Jonathan Wolf: Brilliant. And [00:05:00] last question in this lightning round: Is it true that your gut bacteria like chocolate?

    Tim Spector: Yes. I think they generally do like chocolate if it's good quality, has lots of cocoa, and not so many of the other ingredients. They, most of the average chocolates, I think they probably wouldn't like, but they are going to like high-quality chocolate. 

    Spencer Hyman: It's full of great nutrients and polyphenols and other things, which your gut will love.

    Um, but if it's mass-produced chocolate, it's going to, unfortunately, be full of sugar, which is not necessarily the best thing for your gut. 

    Jonathan Wolf: So Tim, talk a bit more. I think we just started talking about something, which is really interesting. Which is to, you're already saying, um, both of the sorts of different types of chocolate, which I think we'll come on to, but also how it relates to them and these microbes in your gut.

    Can you talk a bit more about why certain chocolates might be good? What's going on with these gut microbes? 

    Tim Spector: Yeah. So you forget exactly what chocolate's made of, but it all comes from a plant, that is. [00:06:00] fermented to give it great complexity. So it's a mixture of fiber and protein and lots of essential nutrients and these defense chemicals that are in the plant called polyphenols. And by fermenting it with microbes, when it's laid out in these hot tropical areas, this breaks down the planted lots of chemicals, and these protective chemicals, polyphenols, are retained in the chocolate. And so when you eat them are then liberated in your gut, and these are like rocket fuel for your gut microbes. 

    Jonathan Wolf: And Tim, will you just remind everybody what fermentation is? Cause you've talked about that being a critical bit, and I'm sure that we'll have Spencer come in a bit about this. 

    Tim Spector: Yeah, sure. The fermentation is a very general word that's used widely, but it means a food that is broken down by microbes to produce other types of food or chemicals. And so this happens when you make cheese or making beer or wine, or, and it [00:07:00] also happens within our own guts all the time.

    Jonathan Wolf: And so this is happening with chocolate, which is, I guess, you know, people think about that for cheese, but I think most of us don't think about that with chocolate.

    Tim Spector: Indeed. Yeah. Most people aren't really aware of where chocolate comes from or how it exactly it’s is made.

    Jonathan Wolf: I thought from the grocery store. I have to admit that's probably...

    Tim Spector: Most people think it grows on trees, but it does actually. But yeah, so the process is very strange and this very complex way of actually making chocolate by which it's dried and which, you know, we can discuss more about, but microbes break it down and produce much more complexity than people think. And so, all the flavors are produced from these complex chemicals of the interaction between microbes in the forest or wherever the pods are left to ferment, getting into the cocoa. And then that stays in that product - in artisan chocolate, at least. And those polyphenols, these defense chemicals, which are the same ones you find in other healthy foods like [00:08:00] nuts and seeds, generally, are retained in the chocolate. And then when you eat it, they go all the way down to the lower intestine and they will then meet your gut microbes. And that interaction between the fiber that's still left in the chocolate and there is fiber in there, plus these polyphenols make microbes happy. They interact with it to produce other chemicals, which we believe are generally good for your body, for your immune system, for your digestion and your mental health, et cetera, et cetera. So it's that complex interplay between the very complex chemistry of what actually is in chocolate, also the complex things that are going on in your own gut that create this healthy effect.

    If you've got a greater proportion of the healthy things in chocolate, compared to the unhealthy parts of the mass-manufactured processed chocolates. So it's getting that balance right. Because on the other hand, if you go [00:09:00] and get highly processed chocolates, mass-produced ones, they will add in all kinds of extra chemicals to bind it together, flavorings, sweeteners. And we know now that artificial sweeteners, so-called emulsifiers, which are like a glue to keep things together, are bad for your gut microbes. And will actually counteract any of the benefits that you might've been seeing. So it's all about not just thinking about chocolate as one thing but realizing that it's a whole spectrum of different qualities that have different effects on your body. Not only just the percentage of sugar but also all the other ingredients that go into making lots of mass-produced chocolates.

    Whereas Spencer will tell you good chocolate has the least number of ingredients. 

    Jonathan Wolf: So eating glue is bad. That makes a lot of sense. I guess I hadn't really thought about chocolate potentially being glue. What's the line and how much of the chocolate that we might see in the grocery store is good chocolate, [00:10:00] how much is bad? How do we actually figure that out? 

    Spencer Hyman: So I think the simple answer to that is that if you compare it to coffee, it's very easy in the case of coffee to tell the difference between instant coffee and a roasted bean. And you can’t forget it's a different process going out. Similarly, if you look at a chicken nugget and you look at a roast chicken, most people can tell the difference. When you look at two bars of chocolate, it's actually a little bit harder and you have to do it in a slightly different way. But to get to the answer to your question, which is “Is most chocolate sold in supermarkets going to be good for you?” Unfortunately, the answer is “no,” it's not going to be good for you. Because it's going to be mass-produced, it will be hydrolyzed in most cases, it will have been fermented because otherwise, you can't get any of the flavor out of it, but it would have been not very well fermented. And then it would have been roasted in such a way; basically, they take the shells off before they roast. And that means that it won't have any flavor because none of the power zones are able to develop. And consequently, you need to add lots of additives to it. And then, above all, the way that most people sort of get [00:11:00] you interested in chocolate, to use a euphemism, is they add lots of sugar, they add lots of fats, they add lots of additives, and they're trying to get you to scoff it rather than to savor it 

    Jonathan Wolf: Does that mean, Spencer, at the end of the day, like the amounts of real chocolate that's left in this thing is really small? It's a bit like other processed foods we might think about where it's been smashed to pieces. There's very little left. That is the sort of thing that Tim is talking about. 

    Spencer Hyman: It's ultra-processed. I mean, most chocolate is ultra-processed.

    In fact, most chocolate is made, you know, the same way that a chicken nugget is made in the sense that the chocolate maker actually doesn't get the beans. He basically buys in something which has already been ready-made and it will have been highly pulverized and processed. Um, and every step of the process, whether, you know, whether it be the fermentation, whether it be the drying, whether it be the roasting, whether it be the crunching, it will be done for efficiency and scale, not for flavor because what you're going to do is use additives later to create that.

    So as Tim said, the most important thing to do when you buy a bar of chocolate is [00:12:00] actually look at the list of ingredients. And if it's got stuff, which is not, you know, recognizable by your grandmother, even if it's something like vanilla, and if it's a dark chocolate bar, be skeptical because they're using that to actually cover up the fact that there isn't much flavor otherwise.

    Jonathan Wolf: How do we figure out a bit more what these differences in chocolate are at a high level? What's the difference between dark chocolate and milk chocolate? What do we actually see at the grocery store? What's the reality out there? 

    Tim Spector: The first thing is that most of the chocolates on sale in, uh, the US and the UK and English speaking countries are milk chocolates. And what people often don't realize is how little cocoa bean is actually in those products and best selling, right in the, in sort of Canada, the UK, Australia is Cadbury's Dairy Milk, which has something around 23, 24 % cocoa content and was nearly made [00:13:00] to be, uh, refused status as a chocolate a few years ago by the European Union because it didn't make status. Because below 30%, I think, was what they were considering you couldn't call it a chocolate. 

    Jonathan Wolf: And something like Hershey's? 

    Tim Spector: Hershey's is around 12%. I think it does vary with the different types, but it's even less than that. And Spencer just reminded me about Bournville. You want to tell them about Bournville Plane, which was one of the first so-called dark chocolates brought to the English market? Spencer tell us about Bournville.

    Spencer Hyman: It's less than 40% cocoa, and that's mainly cocoa solids, very little cocoa butter is added to it. We can go back into what those ones are later, but yeah, I mean, technically, to be called chocolate in Europe, it needs to have at least 20% chocolate, whether it's a milk or a dark chocolate. In the states, that's actually 10%. So that's what it sort of goes from. And most confectionary will have way less than 30 or 40% chocolate inside it. It will be mainly sugar. [00:14:00] 

    Jonathan Wolf: That's amazing, really, right? So if I bought milk, I'd be pretty disappointed if it was only 20% milk. Or if I bought steak and it's 30% steak, I would feel entirely cheated. But that is pretty shocking. Why is that? And at what point, what about the other end? You know, when we start to think about dark chocolate, when does it start to become classified as dark chocolate, and indeed, what's the difference between dark chocolate and milk chocolate?

    Spencer Hyman: So, taking that last question first, technically, the difference is that milk chocolate has milk in it. Slightly confusingly, a number of dark chocolates also have milk in it. You have to look at the ingredient list to check that because often, dark chocolates will have a bulk or a filling agent like whey powder in it. So they're not suitable for vegans. But, in theory, dark chocolate should not have milk in it, and milk chocolate should have milk in it. So I think that what you want to look for is the list of ingredients. And as Tim said, it should be less is more. But I think your questions as to why [00:15:00] is there so much stuff added to chocolate is part of the problem that chocolate has, which is that on the one hand, chocolate is an amazing set of flavors in and of itself. It has more complexity of flavor and taste and texture than just about anything on the planet, including red wine.

    On the other hand, it's also an extraordinarily good vector for other flavors. Arguably it was the first bliss point food. So by bliss point, you know, you guys will know this because your food experts, but the idea that, you know, if you combine sugar, salt, and fat, we all suddenly become unable to resist it. Really the first product to do that was, in many ways, milk chocolate with Nestlé and Daniel Peter back in the 19th century. And that's what really made chocolate take off. 

    Jonathan Wolf: Hence, these like, low fraction of chocolate in the, in the bar, lots of milk, lots of sugar. It gives you this combination of some of the chocolate tastes, but then, so the sugar and the fat which just triggers all of these things that make you want to eat more in a way, which is, you know, very rarely found in nature. Is that what you're saying with the bliss point?

    Spencer Hyman: Yeah, [00:16:00] exactly. And chocolate is an extremely good vector for other flavors and tastes, and sensations. So that's what it's become used for. Not only is it the chocolate bar, which is used in that way, but chocolate is added to other products like ice cream or like cakes, et cetera because it works so well at carrying other flavors and tastes. 

    Jonathan Wolf: So let's talk a little bit about the dark chocolate end. So I think a lot of people are like, “Okay, so I understand that probably Hershey's or Dairy Milk might not be the thing I should be eating. But, I like chocolate because, by the way, I really liked chocolate. Tim, at what point does this dark chocolate start to be good for us? And maybe we can talk a little bit about personalized responses because this is one of the ZOE scores that we definitely look at carefully as we figure out whether we can do this.

    Tim Spector: Yeah. So there's no real consensus about what level of cocoa it starts to be healthy, but it seems to have fallen into this general area above 70% is where most people seem to do that line. But I'm [00:17:00] not sure there's much science saying 65% is bad and 75% is good. But certainly, the more you’ve got cocoa, it means generally the better, the more fiber and the more polyphenols, the more good stuff you've got in there. So, in general, you want to be getting up towards that high percentage, if you can, particularly if you are having chocolate on a regular basis. And, um, as we've all learned, you can train yourself very easily to move up from Cadbury's Dairy Milk to darker chocolates, progressively even if when you make that first switch, it seems quite hard. So everyone's aspiration should be to try and get their cocoa percentage up and work out where their own personal threshold is because everyone will taste things differently and so will have their own personal bliss point if you like. But I think that's what people should aim for.

    Obviously, there are some exceptions because if it's got nuts in it or other ingredients, it makes it quite hard to work out [00:18:00] what the total cocoa content is. So Spencer might know how to advise people on whether once you start adding nuts into it, for example, whether that invalidates the percentage scores. Although I would say that adding nuts - I particularly do like nut chocolate, I know Spencer doesn't agree with me on that one, but, um - 

    Jonathan Wolf: Well, maybe it's good from a health perspective, but as a connoisseur, perhaps, that's a different perspective, right? 

    Spencer Hyman: The nut chocolate, specifically, is whether or not that gets in the way of appreciating some of the nuances of the chocolate, but on the other hand, nuts and chocolate is an amazing combination because you've got lots of texture from it. It is very healthy for you. And, as well, different nuts can bring out different flavors. But I think the main advice is that whenever you buy a bar of chocolate if the first ingredient is not to do with cocoa, be very skeptical - whether it be a milk chocolate, whether it be a dark chocolate. And I think the second one, which is to try and train yourself to savor rather than to scoff. Because to my mind, the reason why I think [00:19:00] - and we should get your perspective Jonathan and Tim's on this - the reason why I think chocolate is a good thing to eat is that I think for most people after a meal, they actually want something sweet. There is this sort of wonderful idea of what the Japanese called setsubara or the second stomach. What it seems to suggest is that even though we are quite full and we've had a whole meal, our bodies actually like having something a little bit sweet, like some chocolate, whether it be dark or milk, because it actually aids digestion. And you could actually see if you take an MRI of somebody after they've had a meal and they're saying that they're very full, if you show them some chocolate or a bit of chocolate cake, they will actually, you'll actually sort of see their stomach move a bit so they can digest a bit more. 

    Jonathan Wolf: My kids have always argued that they have a second stomach for dessert. So I love the idea that there actually is a scientific second stomach for dessert! 

    Spencer Hyman: It's been done live on Japanese TV. And what most people find is if you savor a little bit of chocolate, it does sate and it does fill you up very nicely. [00:20:00] And that to me is one of the strong health arguments for chocolate, which is it's much better to have that than it is to go and scoff some sort of, you know, like low fat, vanilla yogurt, which has actually got seven times the amount of sugar in it than a chocolate bar will have.

    Jonathan Wolf: I have to let Tim say it...he's looking slightly skeptical of the second stomach, so I definitely want him to have a chance to...

    Tim Spector: Oh, I'm a big believer in the Mr. Creosote effect. I think it was the wafer thin mint at the end of the big meal that doesn't always work. Variety is the thing that produces increased appetite. So that's where humans are always looking to get variety into our taste buds.

    Jonathan Wolf: That's really interesting. Sort of talking about sort of personalized responses. You've talked a lot about the way that you're getting over 70%. You're starting to get all these polyphenols and everything that really supports your microbes. I think this is one of these things we also saw a lot of variety in response when we were doing the sort of ZOE PREDICT studies, right Tim? And we see this also in our own personal scores. I managed to just squeak [00:21:00] 50 out of 100 for dark chocolate, which is great news because 50 and above means I'm allowed to eat regularly. Uh, whereas my score for milk chocolate is only 34, so significantly lower. And this is one of those things that made me think, “Oh okay, so dark chocolate is almost the only sort of bad thing that I'm still allowed to do.” Tim, how did you turn out? 

    Tim Spector: Disappointingly worse than you, Jonathan. So I only scored 44 on dark chocolate and 22 on milk chocolate. So I have to be really careful. That really means that milk chocolate, which I've virtually given it up…tastings with Spencer, go for dark chocolate. And that score was for an average between 70 and 85%. I reckon if I go more towards the 80%, I can get my score up a little bit and have more of it. 

    Jonathan Wolf: That makes sense. And there's lots of people with much higher scores for the dark chocolate as well. I think both of us have quite poor blood sugar control, right? And so, this is one of the big challenges with chocolate. It's the sugar that's mixed in [00:22:00] with it, as well as also if you have, you know there's quite a lot of fats so if you have more issues with fat control. So we see a very wide variety in response, but I think in all cases, the dark chocolate is a lot better than the milk for the reasons, Tim, that you were explaining.

    Tim Spector: Yeah. I think I'm at the worst end of the spectrum. So I think most people will be doing probably better than both of us, Jonathan. 

    Jonathan Wolf: Well, but your microbes, always save you, Tim. Your microbes save you as, as always. I think we're starting to touch a lot on chocolate. I know Spencer is keen to talk more about what's going on.

    Uh, I thought it might be fun actually to start with the end product of chocolate before all the boring technical stuff about how it happens. And since we're lucky enough to have Spencer here, uh, he could actually tell us how to taste chocolate. And so I thought, “How great was it that I had a job where I actually had an excuse to eat chocolate in the middle of the day?”

    So I actually brought some chocolate, and, of course, I brought some chocolate from Spencer because Spencer is the man who got me addicted to chocolate [00:23:00] over the last decade. For those of you who don't know Spencer, he's sort of like a chocolate pusher. So whenever you meet him, he takes out of his rucksack, uh, like a bar of chocolate and presses it on you. And you think it's just that he's really generous. But what you realize is it's just a gateway drug. It's sort of like a drug dealer, you know, starting you off. And you're like, “Oh, I don't even know if I like it this much.” You try it a bit. No, that's okay. After a few months, you start to think, “You know what? I’m really starting to like this.” And then you're addicted. So, um, you have to be careful if Spencer offers you chocolate. Talk us through it. I've got some here. Tim and Spencer, do you have some chocolate that we can maybe taste together?

    Spencer Hyman: Yeah, also, we could also do it in a slightly different way. So the one thing I would just sort of pick up on this: I don't believe technically you can get addicted to chocolate. I think you're addicted to the additives inside it, and we've done quite a bit, quite a lot of work on that. Anyway, here's how you should taste chocolate if you want to -  

    Jonathan Wolf: - This, this is, this is what is what my drug pusher says to me as well. Isn't it? 

    Tim Spector: If you get the pure [00:24:00] stuff, you'll be all right, 

    Spencer Hyman: But two cents. So, for example, you do get addicted to caffeine. If you have like four large cups of coffee a day for four weeks, at the end of that, you will get the jitters when you come off it. Similarly, you do get addicted to sugar. You definitely get addicted to all sorts of different, you know, class substances. With chocolate, you would actually have to eat the equivalent of about a kilogram of chocolate a day for ten weeks to get any sort of the, um, withdrawal effects from theobromine. So it's technically phenomenally hard. You can definitely get addicted to the sugar in chocolate. But theobromine, which is the active ingredient inside chocolate, is not as far as anybody's ever shown addictive. So it's not the chocolate that is addictive. It may be the sensations to it, which it arises, which is a great pleasure and great flavors and other stuff. Anyway, let's get back to tasting chocolate. 

    Jonathan Wolf: Got it. So I'm not truly addicted. I just like it so much that I need to keep eating it. 

    Spencer Hyman: It's not like alcohol. It's not like alcohol. So take a piece of chocolate, uh, and do look at it. The most important thing to do with [00:25:00] a piece of chocolate, though, before you eat it is to actually snap it. So if you snap a piece of chocolate... 

    Jonathan Wolf: I'm going to snap this in front of the microphone so you can hear that. Okay. That was a pretty good snap.

    Spencer Hyman: So that snap is really, really important because what it actually says is that the chocolate has been properly tempered, and it's going to melt in your mouth and reduce all those aromas and volatiles and flavors. And if you want to sort of practice at this, a good trick is actually to hold your nose before you grab a piece of chocolate, take a piece of chocolate, and stick it on your tongue. Now, this is what we make everybody do when they come to one of our chocolate tastings because it's a very good way of actually explaining the unique aspect of being human and actually being able to understand the difference between retronasal flavors and olfaction. But if you take a piece of chocolate, you put it on your mouth, you can chew it a bit. You could do whatever you want with it. Now, what you will discover is that you don't get many sensations from it. You may get a little bit of taste. You may have a little bit of sweetness. You may get a little bit of sourness. But, by the time it's melted, [00:26:00] what should happen when you release your nose – Is it melting for you yet? – is that suddenly when you breathe out through your mouth, when you've got a piece of chocolate in it, what should suddenly happen is you should be accosted by a whole wave of aromas and flavors. And what that's showing us is that the amazing thing about chocolate is that when you put it in your mouth, it melts. That's because it's been properly tempered, which goes back to the snap idea. And it's literally the only substance that we have, which, when we put it in our mouths, melts. I know you can say that ice cream does, but it actually melts before you get it in your mouth. So chocolate has this extraordinary ability, next to cocoa butter, when it's tempered to crystal structure five, to melt, and that releases all the flavor volatiles. And because human beings can detect flavor, not just through our noses but also through our mouths because of retronasal olfaction, chocolate is an amazing way of describing that.

    Jonathan Wolf: Not everybody listening obviously is able to have the chocolate at the same time. And the first thing I can tell you is eating chocolate while holding your nose is very disappointing, right, Tim? [00:27:00] There was really no pleasure from that experience, agreed? 

    Tim Spector: No, it's a waste of time. Yeah. 

    Jonathan Wolf: And the second thing is very nice when you stop holding your nose, in general, and even better because then suddenly you've got melted chocolate in your mouth that you can start to taste. 

    Spencer Hyman: And at that stage, it would have melted in your mouth, so it would be releasing the volatiles. And actually, that is, back to Tim's point about looking at the list, sugar, salt, and fat. Sugar, you know, the sort of stuff in dairy milk or in a Bournville or any of those other bars, sugar basically will hit your nervous system in six-tenths of a second. So you will get the hit from those very quickly. Whereas with good chocolate bars, it will take a lot longer…five to 10 to 15 seconds. So you need to train yourself to savor. Um, so that’s sort of the first bit that you should have a bit of fun with chocolate. And then the second bit of advice is always have a couple of different chocolates on the go at any one time because the amazing thing about chocolate is that good craft chocolate, artisan chocolate, they will all taste and have completely different flavors because it has more variety. It's [00:28:00], you know, it's what we love to do with wine, which is have a couple of glasses of wine on the go at the same time. But it's difficult with chocolate. It's actually very easy. You can just crack open a couple of bars, share them with friends, and then you can get into all those different flavors. 

    Jonathan Wolf: Fantastic. Well, I definitely enjoyed the taste of that chocolate. Tim, is what we're smelling also linked to what's going to go on when it hits the gut and all those bacteria get all the good stuff, or are these two sort of completely separate things?

    Tim Spector: Separate but related. Obviously, the greater the complexity of the smells gives you a hint as to all the different chemicals you're getting. I think the better the chocolate is made, just like any food, you'll get this complexity of smells rather than just one strong flavor, which is often artificial. You're getting this complex – a bit like a fine wine – that is developing on the palette. And that tells you that you're likely to get lots of good chemicals that will also reach your gut microbes. So I think that's, they're broadly related. [00:29:00] And so it's a pretty good test of quality, and humans have evolved to actually have pretty good palates if we take the time to use them. 

    Spencer Hyman: Yeah. I think that point about sniffing a chocolate bar is actually a very important one because the way that most mass-produced chocolate is made is such that it is using tastes rather than flavors, and you can't smell a taste. So, you know, sweetness, sugar actually doesn't have a smell. And what you're actually going to get when you get a good dark chocolate or good milk chocolate is you're going to get lots of different aromas. And interestingly, chocolate, unlike, for example, coffee, actually retronasaly and orthonasaly, you will tend to like the smell and like the flavor at the same time, which isn't always the same for coffee. Lots of people like the smell of coffee but can't necessarily eat it. But the other thing I would sort of say is that in craft chocolate, in artisan chocolate, the way the sugar is used is very different. So in a sort of cheap chocolate bar, you're actually using the sugar as the main delight, the main thing, which is going to get you [00:30:00] going. Whereas, as Tim points out, in craft chocolate, what's actually happening is that it's the different polyphenols, it’s the different power zones, it's all the different aromas which cocoa has within it after it's been fermented and dried and roasted, which actually give it all the fun. And what you use sugar for is a little bit like you'd use salt on meat. You can actually use sugar to bring out those flavors. So if you actually get somebody to compare the same chocolate, but with slightly different amounts of sugar, they will have completely different flavor profiles because it's just bringing them out in a different way. But if you're using, you know, a chocolate where the primary ingredient is sugar, all you're really going to get is the sugar.

    Jonathan Wolf: And let's get a little geeky for a minute because it's fun. But, Spencer, you can't spend an hour on this. Tell us a bit about how this works. So we were talking before I think about this idea that maybe 70% plus actual cocoa is a sign that this is probably a good dark chocolate; it's going to start to give you all this positive complexity that supports your microbiome. That's fantastic. But we've also said, “Hey, actually, [00:31:00] there's a difference. All of this is processed, but there's somehow a difference between what's going to allow this to still be a product that has got some health benefits.” So it sort of perhaps balances out some of, some of this sugar and everything else, but it sort of depends.

    So talk us through a bit, like how do you go from this plant in the jungle, right? Somewhere to something that is, you know, in all cases, a bar that really doesn't look very much like a plant at all. And, um, help us understand a bit about what's going on there and therefore how we can figure out not only by buying a product from you, clearly, but let's say you go to the grocery store, we've got to be practical. What helps us to identify the sort of stuff that actually, you know, day to day we could be eating. It is a, um, it's a nice treat. I'm even if you say I'm not addicted, I'm addicted. What's going on? And how can we sort of recognize something that we should feel good about eating? 

    Spencer Hyman: So I think let's start with the last point, which is “how do you identify something good?” There are basically three things you should look at whenever you buy a chocolate bar. The first thing is the ingredients and the first ingredient should not be sugar. It should be [00:32:00] chocolate. Um, whether that's a milk chocolate or whether that's a dark chocolate, even a white chocolate, when we sell white chocolates, the first ingredient is always going to be cocoa or cocoa butter. 

    And you don’t want to have a bunch of additives and stuff that your grandmother wouldn't recognize. And we'll come back onto that in a sec. The second thing you'd really like to know is actually where did the beans come from? Because that's quite important because it has all sorts of flavor implications as well as also having all sorts of socioeconomic implications, which we maybe can touch on in a sec. And then finally you want to know where it's made, because as I said, most chocolate is actually made rather like chicken nuggets not made, uh, like, you know, the way that you'd sort of make a roast chicken. This sort of, I think, so you want to know literally, where is it being made? So, you know, the bar that you have in front of you, Jonathan, you know, the beans that come from a small bit of Columbia called Arauca, and they are sailed over on a ship as you delight it to, to Mike Longman at Chocolarder down in Cornwall. But what they're trying to do is bring out the flavor of the chocolate. And I [00:33:00] think, you know I think you've covered in other aspects of the podcast, “What is ultra-processed food and how does that work?” And in a way, what you want to try and do is get to what we call craft chocolate, which is not ultra-processed. And every step of the way, craft chocolate is different to mass-produced ultra-processed chocolate. The very first step, as Tim's sort of said, is, hey, remember chocolate is a fruit. You know, it does grow on trees. It looks a bit strange. So for those of you who can't see it at home, I'm holding up something which looks like a small rugby football. Um, and it's got lots of different colors on it, and they are wonderful colors. And when you open it up, it tends to look, uh, rather like something like an alien. I don't know if you've ever seen this, Tim, obviously, you would have because of where he's been in Costa Rica, but you have these sort of rather sort of strange white seeds covered in a pulp. And as Tim said at the beginning, the magic of chocolate - 

    Jonathan Wolf: - and those just described, and they're like about an inch long, three centimeters?

    Spencer Hyman: They’re about an inch long, maybe a little bit less. You have about 25 to 50 of them in a pod, which is about enough to make one chocolate bar. And as an aside, you actually need one and a half [00:34:00] thousand to 2,000 liters of water to grow one of these pods. So you need a lot of it, which is why chocolate, if it involves deforestation, is so disastrous. But these seeds are incredibly bitter. If you put one of these in your mouth and you try and eat, it is incredibly bitter and astringent. 

    Jonathan Wolf: And Tim, that is your polyphenols that you're talking about, isn't it? That you were talking about earlier, I guess?

    Tim Spector: The chemicals that give you that astringency, that, you know, set that really quite bitter, very bitter taste are all these defense chemicals, which are good for the plant and if you use them right, good for us as well. But they are defense chemicals which stop other insects from eating them and other plants from eating them directly. 

    Spencer Hyman: Yeah. And it's the magic of fermentation which turns these incredibly bitter and astringent seeds into cocoa beans. Because what happens is all the way through - so the first thing happens that is fermentation, and that's a yeast-based reaction with the sugars in the pulp reacting to create a [00:35:00] fermentation - but all the way through whether you're fermenting, whether you're drying, those are the first two tests that you have on the farm. And what's actually happening is, is that you're creating heat and what heat does is it basically breaks down the power zones or the polyphenols in the chocolate to start releasing aromas, which we can then detect later in the process. So after the chocolate, the cocoa seed has been fermented and then dried, it will then generally get sorted. And most of the time, it will then get sent to a factory. And this is where the first big differences start to occur because the mass-produced chocolate, you don't really care about the fermentation or about the drying because you're going to add flavoring later. But for craft chocolate or artisan chocolate, you can create all sorts of different flavors just as you can with wine. The different fermentations you're going to have will make a huge difference, as does the drying. And then when it gets to the factory, you have to make a decision. The first decision is, are you going to go for efficiency? And if you go for efficiency, you take the skins off the bibs off the beans and then roast it because it's a bit more efficient. But if you do that, [00:36:00] you lose the ability to control much of the flavor. So that's not what craft chocolate does. So what craft chocolate will do is it'll roast the beans from about 30, 20 to 30 minutes. And then again, the heat will create mild reactions that will bring out more flavors. Then what you'll do is you'll take the shell off. You'll do what's called winnowing and conching, which is to grind it into a paste, into a smooth paste. Tim is actually trying what we call stone-ground chocolate, which hasn't been conched. But again, it's heat, which is being applied at this point. And then you'll temper it and then you'll turn it into a bar. Now with mass processed chocolate, they'll use a whole bunch of other technologies, which you wouldn't be able to do at home. Again, it's like ultra-processed food. Like they’ll hydrolyze it. They will add a lot of other stuff to it that you wouldn't really want. They'll often actually not add cocoa butter, but what they'll do is they'll add vegetable fats and carb oils and stuff like PGPRs. And then we can also talk a little bit about, you know, lecithins and other glues, which are definitely problematic. But in the end, what you'll have if you have a good artisan chocolate, or a, you know, a reasonable chocolate, you will have [00:37:00] hopefully some of the flavor of cacao coming through, which is the great fun part to it. If you don't, it will still be a pleasant experience, but what you'll basically be doing is using the chocolate, its mouthfeel, and its ability to basically be a great vector for other flavors. And it won't necessarily be that great for you. 

    Jonathan Wolf: We couldn't cover this conversation without talking about the sugar, right? So most of us are not going to be eating a hundred percent chocolate bar. There is sugar being added. You've talked about that already. Uh, Spencer, about the balance, like how bad is that? It's got sugar added to it, so this is like a terrible thing. Like how do we think about that? 

    Spencer Hyman: So I think that that's a slight red herring and a bit misleading, um, because the amount of sugar in a 60 or 70-gram bar of chocolate, which is 70 or 80 percent, is one or two teaspoons, and you're never going to eat a full chocolate bar in one sitting. Well, you know, I would suggest that you don't, you don't need to if you savor it and you appreciate the flavor. 

    Jonathan Wolf: I can manage it. But all right. 

    Spencer Hyman: I don't know if you'd eat a full chocolate bar. Very few [00:38:00] people will actually take a good quality artisan chocolate bar and actually scoff it in one go…unless they're incredibly hungry, in which case it's probably not the ideal thing because it's something which you wants to savor. It's a bit like, you know, for most people, you don't really drink a whole bottle of wine in one go. And actually, let's compare it to an American red wine. A lot of American red wines, uh, you know, the high alcohol ones, will actually have more sugar in them than a bar of chocolate. Certainly, a low-fat yogurt, a low-fat vanilla yogurt, has got like five or six times the amount of sugar than a dark chocolate bar will have.

    Jonathan Wolf: And you’re particularly talking about a dark chocolate here, right? Cause again, just to remind everybody, milk chocolate falls, right? They tend to see higher sugar levels?

    Spencer Hyman: Yes, but there is a sort of slight twist on this, which is that when you talk about milk chocolate and dark milk chocolates if they're good quality, we sell a lot of milk chocolate bars, but almost all of our milk chocolate bars are over 40% cacao. And once you start getting above 55, 60%, actually they have less added sugar to [00:39:00] them than a dark chocolate bar or 70 or 80%, because actually the milk is being caramelized and becoming a sweetener. We actually do some chocolate bars, which are milk chocolate bars but have no added sugar. So that 65 or 70, or even 80% cacao, and the sweetener is milk. Now obviously, as you caramelize the milk, it does become a sugar, but I'm just sort of encouraging you to think slightly differently about sugar. What's really dangerous is if the chocolate doesn't have any flavor naturally. And that's, I think, what Tim was sort of saying. So that is the important thing about, you know, the great thing about food is if it has flavor, then it's more much likely to be natural. And chocolate is an absolute perfect example of that. The more flavor the chocolate naturally has, the less processing that it's going to have unless, you know, the ultra processing that it will have had with it. But I wouldn't worry too much about dark milk chocolates. and good craft milk chocolates. The only danger I think is that you tend to scoff [00:40:00] more of them than a dark chocolate bar. I think that's where it becomes trickier. That a milk chocolate bar is much closer to a bliss point food than a dark chocolate bar. And again, the bliss point is what you described earlier on when you combine sugar, salt, and fat. Human beings just don't know how to stop eating. 

    Jonathan Wolf: Brilliant. So we actually asked our ZOE members on Instagram, and we said we were going to be doing this really fun podcast, talking about chocolate and what were their key questions and a number of them we've already covered, but there are a number here that we haven't. And so I want to make sure that we've covered those. One question was, is fruit and nut milk chocolate healthier than dark chocolate? Tim, I can see you've been thinking about this. What's the answer? 

    Tim Spector: Well, it's always going to depend on which we're comparing. On average, it would be less healthy than dark chocolate, just because of the way they're made, and generally, fruit and nut chocolates tend to be made with very commercial milk chocolates or low, you know, uh, cocoa quality and amount. So you're mainly [00:41:00] having sugar and dry fruits are a very, uh, high source of sugar as well. So probably the only good bits you're getting there are a few nuts in that one. So although I, you know, used to love, um, as those were my favorite as a kid, I think fruit and nut chocolate, I now realize it's not… definitely not a health food. 

    Jonathan Wolf: So I'm afraid fruit and nut milk chocolate is out, it sounds like. So next question: How much chocolate do you need for it to be beneficial? So I love this question where the question is really, “am I eating enough chocolate in order to get the benefits,” which is a wonderful way to think about this.

    Spencer Hyman: So I think there's sort of a couple of different ways of answering this. I think if you eat enough to stop you having a third slice of chocolate cake or, you know, a fifth piece of, you know, sort of black forest gateau, then that's a good thing. I mean, I think what I think chocolate is, is it's a great way of satisfying your cravings for sweetness at the end of a meal without [00:42:00] having too much of it. On the other end of it is there is, as Tim was sort of saying, there is some evidence actually that the polyphenols in chocolate actually can be very beneficial for your heart. And there is this tribe of people in South America called the Una, and the fact that they never have heart attacks is put down to the fact that they drink about 15 to 17 cups of chocolate every day. So, you know, if that's what you're after, you've got to consume an awful lot of it. Um, and I'm not necessarily sure that most of us would be up for being able to sort of do that. It's sort of like, you know, the way they drink it is definitely slightly differently to the way we would consume it.

    Tim Spector: I'd say quality, not quantity is what people should be aiming at. 

    Spencer Hyman: 20 to 25 grams a day, which is a quarter of a bar, which is what you'll get, actually, when you come to one of our tastings, that's what people will eat. They're amazed. They're absolutely full by the end of it, but they've literally had less than a quarter of a bar of chocolate, but they’ll have had about ten different chocolates in about that amount.

    Jonathan Wolf: Brilliant. So next question. Should I [00:43:00] watch out for lecithins in chocolate? 

    Tim Spector: Lecithin is an emulsifier, which is the glue-like substance that binds things together. So it's an indicator that whoever's making that chocolate is trying to cut some corners and, uh, and stick some of these things together. There are many emulsifiers used in, um, in food processing, and probably lecithin is one of the healthier ones of those because it is a natural product. But it generally is a sign that someone is cutting corners with a process. And so, um, and there's a question mark about whether lecithin itself may be harmful for your gut microbes. So yeah, it's probably not terrible, but it's also a sign that you could do better. 

    Spencer Hyman: In chocolate, there are generally two leci-, well there's three lecithins, which you use, one of which I'm going to ignore immediately, which is PGPR because it's used as an alternative to vegetable fat. It's just really, really bad. That's just not a good thing. Um, the other two are [00:44:00] sunflower lecithin and soil lecithin. Of the two, always look for sunflower. And as Tim said, the reason why lecithins are added to chocolate is because it helps people who are cooking with chocolate. If they're trying to make, you know, some sort of great chocolate pudding where they want a glaze, it makes it much easier to deal with. But also because in hot countries, which rarely make chocolate - so most of the time actually where chocolate is grown is not where it's made - um, but in those few cases like Madagascar with someone like Menakao the machinery gums up if you don't add a bit of lecithin to it. So then it's the exception that proves the rule. But generally, be really dubious about ingredients. I mean, I would be much more worried about vanilla or vanillin, especially in dark chocolates, uh, than I would be about lecithins. But if you can, yeah. I mean, you know, less is more.

    Jonathan Wolf: Brilliant. And last question. Is eating half a bar of chocolate just before bed a bad idea?

    Spencer Hyman: This is an interesting one because [00:45:00] actually one of the interesting things about drinking chocolate is that people have always often had it before bed because it does, it has this, it does help people sleep - hot drink before you go to sleep. And although chocolate does have trace elements of caffeine, its main active ingredient is theobromine, which has this sort of weird effect of, on the one hand, stimulating you but not sort of waking you up. Um, I think there the argument about like having, you know, half a bar of dark chocolate again is going to be, you know, what sort of dark chocolate is it? If it's a dark chocolate bar, which is like, you know, 60% sugar, then be a bit worried about it because sugar is going to keep you up. Um, I'm not necessarily thinking that half a bar is necessarily good. A couple of squares will definitely, you know, cause your second stomach to regurgitate in a very good way, so that may help you sleep. Um, but I, you know, I'm not sure that eating before you go to sleep is overall a great thing, but Tim, you're the expert on this. 

    Tim Spector: Yeah, in general, uh, I think you should be having your chocolate not just before you go to sleep but have it just after your meal [00:46:00] or just before a meal. Um, and you want to keep up…there's a general idea that we want to put our eating times together and we have to wait a long time for our gut to recover. So, uh, I'm against late-night snacking or early morning snacking. Give your gut rest and, uh, let it enjoy the chocolate, uh, in its eating time and not confuse it.

    Jonathan Wolf: Brilliant. I think that's a perfect place to stop. This has been so much fun. I think we could keep talking about chocolate for hours, but we will, we will stop. Thank you, both Tim and Spencer, for joining me on the ZOE science podcast today. We hope you liked today's episode. Please be sure to leave us a review and subscribe if you did. If you're interested in learning more about ZOE and the best foods for your body beyond chocolate, you can head to joinZOE.com/podcast and get 10% off your personalized nutrition program. As always, I'm your host, Jonathan Wolf. The ZOE Science and Nutrition podcast is produced by Rob Heath with support from Sharon Feder here at ZOE. See you next [00:47:00] time.

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