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To get started, go to audible.com/scishow or just text “scishow” to 500 500. [INTRO ♪]. Protein has been an important component of human diets since forever, and so too has the consumption of meat.

But nowadays, there are a number of religious, philosophical, health, and environmental concerns associated with the amount of meat people are eating. Like, I've talked over and over again about how our love of meat—my love of meat—is harming our planet. And meat consumption in places like the US has continued to rise over time even though we already eat way more meat than we need to nutritionally.

So perhaps it is not surprising we've seen a number of companies lately trying to steer consumers away from their favorite meaty foods. I'm talking about things like Burger King's Impossible Whopper, fishless sushi, or Quorn—which, despite the name, isn't corn-based at all. All of these explicitly aim to get carnivores like me to come over to the veggie side.

Now, people have pretty much always had non-meat options for protein, of course. Tofu has been popular for well over a thousand years, and it's only one of the many options at the table alongside products like seitan or tempeh. And we even have newer tasty things like Morningstar Farm's veggie corn dogs, which I'm a pretty big fan of.

But simply having these vegetable proteins available hasn't really reduced our overall consumption of meat because, well, people like me like meat. Studies have suggested that the best way to make meat substitutes attractive to non-vegetarian consumers isn't to talk about abstract things like ethics, but instead, to actually get the stuff to look and act and taste like meat in a recipe. The thing is, mimicking meat is not as easy as, say, slathering something in barbeque sauce and sticking it on a bun.

So today, we're going to break down some of the challenges and the science behind making meaty fake meats. Let's start things off with beef— and specifically ground beef. It's one of the meats that protein producers would really like to be able to replicate because we love burgers.

You'd think ground beef would be a fairly easy one, too, if you can nail down the taste part, because everything's all ground up anyway. Still, you've got to give it the right look. You see, your first impression of a piece of food is often through your sense of sight, rather than your taste or smell, and studies suggest that this first impression can actually modify the flavor you perceive, a type of cognitive bias that scientists call a “halo effect”.

So to really make a believable fake beef patty, you need something that bleeds like real red meat. Technically, “bleed” is not the right word for this, because the reddish juice that comes out of a steak or a cooking hamburger is not blood. It's water mixed with broken down bits of the tissue itself, and the color actually comes from a molecule called myoglobin.

Myoglobin is a protein in muscle cells that helps them carry and store oxygen. It's similar to hemoglobin, the oxygen-carrying molecule in red blood cells. Both of these proteins get their oxygen carrying capacity and their red color from a molecule called heme.

Now, heme is made up of a single iron atom surrounded by what's known as a porphyrin group made of nitrogen, carbon, and hydrogen. Each heme group can bind to a molecule of oxygen. When meat is cooked, the muscle fibers in it start to break down and release their myoglobin, which combines with moisture and other compounds being squeezed out by the cooking meat to form that fluid that gives the signature “bleeding” effect.

And this isn't just a visual thing. The heat breaks apart some of the myoglobin protein, too, releasing heme and some of the iron. That iron, now free, catalyzes chemical reactions that produce much of the aroma and flavor compounds which give cooked beef its smell and taste, as well as helping color the char on the meat.

There are a couple ways you can approach recreating this effect, and different companies have different ways of making their fake beef more beefy looking. Beyond Meat uses plant colorings like beet juice to recreate beef's color, for example. Impossible Foods, another meatless meat producer, has taken a different approach.

They're mimicking the myoglobin itself by adding a plant-based compound called leghemoglobin to the mix. Leghemoglobin is another protein that helps transport and bind oxygen— one that also uses a heme group, and even has a similar structure and the same, ancient evolutionary origin as myoglobin and hemoglobin— but it is not found in muscle cells. Instead, it was originally found in cells in the root nodules of legume plants like soy and beans.

There, it helps get oxygen to the symbiotic bacteria that live inside the root nodules, which take nitrogen from the air and turn it into compounds the plant can use to grow. That's the original source of leghemoglobin, anyway. But there isn't really enough there to make extraction for this purpose practical.

Digging up these plants and pulling the leghemoglobin out of their roots would simply take too much time and money. So Impossible Foods uses transgenic yeast instead. Thanks to genetic engineering, they were able to insert the gene responsible for creating leghemoglobin into yeast cells, which are relatively cheap and easy to grow.

Then they extract the protein from these yeast. By adding these yeast-produced proteins to a mix of other protein material from plants, they can better simulate the look of actual red meat. >>

Hank: Time for a taste test. >>

Stefan: Yeah, we're gonna test out—ah, we have three different kinds of food: fake meats versus real meats. >>

Hank: Okay. It's a double-blind, so nobody in the room knows the contents of this envelope, so not even our researchers are aware. >>

Stefan: Yeah. We don't know, we have different plates. >>

Hank: Sam will tell us if we get things right. >>

Stefan: So the first thing we have are two burrito bowls, and they're labeled A and B. >>

Stefan: And, like, as we said, nobody knows which one of them is the impossible beef. >>

Hank: Okay. >>

Stefan: And then one of them— >>

Hank: Beef beef? >>

Stefan: —is just a regular beef beef burrito. >>

Hank: You're not a vegetarian, are you? >>

Stefan: No. >>

Olivia: Oh, hell no. [Laughter] >>

Hank: Okay, ‘cause that would make this a really hard experiment to do. >>

Olivia: It would. [Struggling with bowl] [Beep] >>

Hank: Alright, A or B? [Forks clattering] >>

Stefan: Okay. >>

Hank: Oh, I see a little—I see some beef here. >>

Olivia: Alright, yeah. >>

Stefan: Let's get some—yeah. >>

Olivia: Alright. [Chewing] >>

Hank: That tastes like real meat to me. >>

Stefan: I made a good choice. >>

Hank: But maybe it's not. >>

Olivia: It's a little too—mm hmm. >>

Hank: Now that it's spent a little bit of time in my mouth. >>

Olivia: It gets weird after a minute. >>

Stefan: Interesting. >>

Hank: Yeah, that first bite was like, “That's—” and I was like, “They put a lot of meat flavor in that meat.” [Laughter] >>

Olivia: Yeah. >>

Stefan: Well, let me—let me cross over, here. >>

Hank: Should I not have said anything? So many arms. >>

Olivia: Yeah. >>

Stefan: Just six. The normal amount. >>

Hank: Well, that tastes like fake meat to me now, too! [Chewing] >>

Olivia: I still think that one's real. >>

Hank: You think that—? I think that one's real! >>

Stefan: I think I'm just gonna get a little bit of the meat, just the meat. >>

Hank: Yeah. >>

Olivia: They're both weird, so it's hard to tell. >>

Hank: Yeah. They're very similar. >>

Stefan: Yeah. That's incredible. >>

Hank: Are you sure they're not both fake? [Laughter] >>

Stefan: I'm pretty sure! >>

Hank: I think A is fake. You think B is fake? >>

Stefan: I think B is fake. >>

Olivia: I do too—yeah, I still think B is fake. >>

Stefan: What's the answer, Sam? >>

Sam: A is the real meat. >>

Hank: Ahhh! >>

Stefan: Yeah, okay. >>

Sam: B is the imitation Impossible Burger. >>

Hank: They—oh, god. >>

Stefan: It's impossible beef. >>

Stefan: I'm very familiar with ground beef. >>

Hank: Okay, yeah, I guess. >>

Stefan: Yeah, yeah, yeah. >>

Stefan: This one has a little more moisture to it. >>

Olivia: This one's spongy. >>

Stefan: Maybe people are after that. >>

Stefan: It's spongier! >>

Hank: Yeah. >>

Stefan: That's a good way to describe it. >>

Hank: Sorta bounces. >>

Stefan: But they're very close! Like, I think I would only notice because I'm eating them back-to-back. >>

Hank: Right. >>

Olivia: No, totally. >>

Stefan: Like, if I just ordered that? Like, I wouldn't know the difference. >>

Hank: It's more seasoned, too, which I think maybe covers up some of the fake-iness. >>

Stefan: Yeah. And it's in a burrito bowl, which helps. >>

Hank: Yeah. Bye, everyone! [Laughter] >>

Stefan: Lunchtime! Other faux meat producers are similarly invested in the visuals of their products. For example, a company called Sophie's Kitchen uses turmeric to paint orange stripes onto shrimp substitutes. But no matter how good something looks, you also have to get the taste right, too.

So all the different groups trying to make fake meats end up asking themselves the same question: what makes meat taste meaty? Heme is part of the answer for red meats, but seafoods are a whole other barrel of ... fish, obviously. Still, if you go to certain markets, you can get something that looks and tastes like fresh tuna.

Except, it's actually a Roma tomato that's been peeled, de-seeded, and cooked sous-vide. And tuna's not the only seafood that's being mimicked, either. Other producers are creating faux salmon, shrimp, calamari, scallops, and more.

This'll be great because I can't eat scallops or I'll die, so I can have a fake one! Capturing a fish or shellfish's essential seafoodiness ultimately comes down to understanding the compounds most responsible for its smell and taste. But meats can contain thousands of different chemicals that contribute to that odor and flavor.

And each different type of meat will have its own chemical fingerprint of sorts. In seafoods, sodium, potassium, chlorine, and phosphoric acid commonly contribute to that fresh-from-the-sea taste, for instance. But one thing all meats seem to share is a savory “umami” taste.

According to some researchers, capturing that umami flavor is one of the biggest keys to a successful meat substitute—and one of its biggest challenges. Umami, or just “savoriness” is one of the five basic tastes, along with salty, sweet, bitter, and sour. Chemically, umami can come from a number of things, but most notably, it comes from compounds called glutamates.

These are found in red meat because the amino acid form of glutamate, glutamic acid, makes up about a fifth of the amino acids found in animal proteins. Lots of different seafood is especially high in glutamic acid as well. But though these chemicals might be part of that signature meaty taste, they're not exclusively found in meat.

You can get glutamates from other sources. Seaweeds, soy sauce, mushrooms, and yeast extract can all add umami flavor. >>

Hank: We walked into this room and Olivia said, “It smells like the inside of a chicken nugget in here." >>

Olivia: And it does. [Laughter] >>

Hank: It's like—it's like the smell of chicken nugget— >>

Stefan: Oh, I'm loving it. >>

Hank: —has been distilled, and it's like when they, like, make buttered popcorn jellybeans, but with chicken nuggets. Okay. >>

Stefan: We've got some fish sticks. Ooooh. >>

Hank: Wow, those are bright! >>

Stefan: Very differently colored! [Laughter] >>

Olivia: Wow. >>

Hank: I mean, also both look fake. >>

Olivia: Uh-huh. Well, yeah, it's hard to tell when things are, like, this processed. >>

Stefan: Yeah. >>

Hank: Yeah. What fish is swimming around that is that rectangular? [Laughter] >>

Hank: Okay. >>

Stefan: Oh, boy. >>

Hank: I'm gonna start here with the less appetizing looking one. >>

Stefan: Yeah, let's—okay, sure. >>

Stefan: Yeah, these have a nicer golden color, I guess. I don't know. >>

Stefan: Mmm. The initial taste was better. [Laughter] >>

Hank: What are—it tastes like a fish stick to me. >>

Stefan: It's okay. It does taste like a fish stick. >>

Hank: It tastes like a fish stick that's been microwaved, though. >>

Hank: That seems real to me. >>

Stefan: It felt real, yeah. >>

Olivia: Mm-hmm. It's got some, like, color variation. >>

Hank: The coloration? Yeah. >>

Stefan: Ooh, yeah. I bet they would do that on the fake fish, though. >>

Hank: This looks like fake chicken nugget. It doesn't flake like fish. >>

Olivia: Yep. No, this is the fake one for sure. >>

Stefan: Mmm. Yeah. >>

Hank: But I don't dislike it. It's funny because this one looks faker because it's so bright yellow. >>

Stefan: Uh-huh. >>

Olivia: This one tastes so much fishier. [Laughter] >>

Stefan: Really? >>

Olivia: Yes! >>

Stefan: I was gonna say this tastes more like ... >>

Olivia: Not in a good way. >>

Stefan: ...a bad chicken nugget. >>

Hank: Right. We're saying that B is real. All of us agree. >>

Stefan: Mm-hmm. What's the answer? >>

Sam: A is imitation, and B is fish meat. >>

Hank: B is fish meat. Yeah, that was pretty clear. >>

Olivia: Yeah, definitely. >>

Hank: Still, I'd eat this all day. >>

Stefan: Oh. No, no, no. >>

Hank: Maybe with some ketchup, though. >>

Stefan: You want some ketchup? >>

Hank: Oh! Thanks! [Laughter] It turns out some edible plant parts, like tomatoes, are naturally high in glutamic acid— which is why, combined with their red color, they're such a good choice for fake tuna. As for ending up feeling like tuna, well, two parts of the low, slow, and precise cooking from sous vide may be responsible for that. For one thing, the heat from cooking can make starches found in plant cells become gelatin-like while breaking down the cell walls.

Secondly, sous vide items are typically vacuum sealed to increase heat transfer from the water to the food, but putting the fruit in a vacuum can make the tissue expand, and when the pressure is restored, the tissue collapses down, becoming denser and kind of meaty in texture. Of course, seafoods tend to be softer to begin with—not all faux meat textures are so easy to get right. If you've ever cut up a chicken breast, for example, you'll notice that the meat has a kind of “grain” to it, like a piece of wood.

That's because muscles are made of long, narrow cells called muscle fibers. In skeletal muscles—the kind of muscle that animals use to move their bodies and which makes up a chicken breast or drumstick—the cells are arranged in long bundles surrounded by connective tissue. Most of the space in these long cells is filled with myofibrils: the cellular compartments that contain the stringy proteins which do the actual lengthening and shortening of the muscle tissue, and they are the main thing that gives meat its texture.

And getting this texture right seems to be an important part of making faux meat attractive. For example, a study from 2013 exploring how much consumers liked meat substitutes found that people didn't like textures that were too soft. They wanted something that was, like, chickeny.

Replacing the protein content of chicken is straightforward since plants have plenty of proteins, but the plant proteins we use for faux meat don't come in these long, aligned bundles. They're more bunched up in what chemists would call a globular structure. The challenge is figuring out how to turn those bunched-up proteins into a fibrous, three-dimensional, meat-like shape.

One method is to extrude them—a process which looks a lot like making pasta noodles or something. But the pressure and temperature are way higher, and the scale is way bigger. You start with plant protein.

Legumes like peas, soy, or beans have a lot of protein, so they're usually a good place to start. This protein is extracted— soy beans, for example, get a series of washes and soaks before being dried— and then put into a machine that looks kind of like a pasta press. There, it's heated, which helps breaks the molecular bonds holding the globular proteins together—like disulfide bonds, which link sulfur molecules.

Breaking these bonds causes the proteins to lose their shape and unravel, a process known as denaturing. Then, the pressure and flow in the extruder causes those now looser, stringier proteins to align more linearly. And as they reach the end of the extruder, they're cooled, which allows the reforming of those chemical bonds to ensure they keep that fibrous texture.

Once that's done, they can be shaped into strips or crumbles, colored, and flavored further, and eventually shipped off to a store. So, that's one way to do it. On the other hand, you could start with something that is more fibrous in the first place.

Quorn is a meat substitute made from a filamentous fungus, and therefore it is what's known as a “mycoprotein”. These meat substitutes are somewhat like muscles in that they're made of a mash-up of cells arranged in very fine fibers, though these cells, called hyphae, are more branch-shaped. To make quorn, hyphae are mass-produced through fermentation—when harvested they apparently look kind of like bread dough.

The “dough” can then be heated and centrifuged to recover the fibery proteins. These are then mixed with a binding agent and flavors, and extruded in a process similar to how the plant proteins were to make them even more meaty in texture. >>

Stefan: And lastly, we've got some chicken. >>

Hank: Ooh! >>

Stefan: Ooh, woah! >>

Olivia: Very strange. >>

Hank: Yeah! >>

Stefan: These are seasoned. >>

Hank: Yeah, much more heavily seasoned. >>

Stefan: Which makes me think it's fake. [Laughter] >>

Stefan: Just right off the top. I'm like, "you gotta season it?" >>

Hank: They gotta try harder on the fake stuff. >>

Stefan: Try to hide it a little bit. >>

Hank: Yeah, whereas these look terrible and so must be real. [Laughter] >>

Stefan: Why do we start with B? >>

Olivia: I don't know. >>

Stefan: Yeah, they are terrible. >>

Hank: But it definitely tastes like chicken. >>

Stefan: It tastes like chicken. >>

Hank: It had the—the chicken taste. >>

Stefan: Yeah, it does! >>

Hank: Like, very strongly, even. >>

Stefan: A little too chickeny. >>

Hank: Like—yeah, like they concentrated it and poured it on them. >>

Stefan: Yeah! >>

Stefan: I don't like those, but I think they're real. >>

Hank: I do like them, which says a lot about me. [Laughter] >>

Stefan: You want some barbeque sauce? >>

Hank: Hell yeah! >>

Hank: Hey! >>

Stefan: Well, don't cuddle it. Let's get— >>

Olivia: It's beautiful. >>

Stefan: —let's get some sauce on there! [Laughter] >>

Hank: Stefan's like, “this isn't helping me.” >>

Stefan: We're—I haven't had lunch! >>

Olivia: Yeah, I think I have to try the other one before I can tell which one—what I think of this one. >>

Hank: You're not convinced? That that's real? >>

Olivia: I'm not. >>

Stefan: It's good barbeque sauce. >>

Olivia: It doesn't look like anything recognizable. >>

Hank: Well, that's how chicken nuggets work. >>

Olivia: I guess that's true. >>

Hank: Alright. Better looking but probably fake. >>

Stefan: Oh, got a good crisp. >>

Hank: Now I'm not convinced! >>

Hank: No, it's fake. >>

Stefan: It's fake. >>

Olivia: I mean, even if it's fake, the texture of this one is way more appealing. >>

Hank: Yeah, I agree. >>

Stefan: The tex—oh, yeah, yeah, yeah. Alright. >>

Hank: We think that A is imitation. >>

Sam: A is indeed imitation. >>

Hank: Oh, thank goodness. >>

Stefan: Oh, yeah! >>

Hank: I like the fake one better, but yet I'm going back to the real one. >>

Stefan: No. [Laughter] >>

Stefan: You're wrong. You've made the wrong choice. Some are actually trying to take this idea of mycoprotein one step further by convincing fungi to grow in more muscle-like structures with the help of edible trellises— so you wouldn't need the extrusion process at all. But, of course, there's more to making a believable fake steak than getting a fungus to grow in a more steak-like way.

After all, the texture of your meat isn't just a matter of protein. Impossible Foods reportedly uses coconut oil in its burgers to mimic beef's fat, for example. It turns out that meats are remarkably complicated mixtures, and getting things to look, taste, and feel the same is an equally complicated challenge.

But, scientists are rising to meat it. Because we eat with our eyes first, researchers have found ways to make their fake meats look more convincing—like burgers that really do leech heme-juice. And by diving into the chemistry of how tastes work, flavor scientists have discovered how to use glutamates to bring meaty umaminess to plant-based foods.

Some have even found ways to mimic the biological architecture of muscles to get the texture of meat mimics just right. There's still a lot to figure out, though—after all, fake meats don't always fool us. >>

Olivia: I think that the beef was the most impressive. >>

Stefan: Yeah. >>

Hank: Yeah. >>

Stefan: Definitely. There's no reason to season a chicken nugget. [Laughter] >>

Stefan: Unless it's fake. And I've yet to see a believable meatless T-bone. But with so much being invested in mimicking meat, in the near future, people might actually be able to eat a more plant-filled diet without giving up the meaty foods that we love so much. And that would be great, because pretty much everyone who eats meat, myself included, should be eating less of it, or even none at all.

I just really don't want to give it up. Corn dogs! If you want to learn more about the foods we eat and their relationship to our health, you might like my friend Aaron Caroll's audiobook The Bad Food Bible.

In it, he does a fantastic job of explaining how it's not so much the food itself but our relationship to it that's really unhealthy. And you can listen to it for free thanks to Audible. You see, Audible has the largest selection of audiobooks out there.

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And you can get your first audiobook for free when you try Audible for 30 days. Not only that, but you'll get 2 Audible Originals for free, too. So if free audiobooks are your jam or you think they might be, you can visit audible.com/scishow or text “scishow” to 500 500 to get started. [OUTRO ♪].