• Sound is the forgotten flavor sense

    Composers have written music to go with feasts and banquets since antiquity—indeed, in at a particularly spectacular dinner hosted by Duke Philip of Burgundy in 1454, twenty-eight musicians were hidden inside an immense pie, beginning to play as the crust was opened. Today, however, most chefs and restaurants fail to consider the sonic aspects of eating and drinking. That's a mistake, because, as we reveal in this episode, sound can affect how fast we eat, how much we're prepared to pay for our meal, and even what it tastes like.

    Don't believe us? Here are three simple sonic seasoning tricks to try at home:

    THE SONIC CHIP

    This experiment, for which Charles Spence won a highly coveted IgNobel prize in 2008, came about almost by accident. Spence was working with a big company to see whether they could use the recently discovered "parchment skin" illusion to trick customers' brains into believing that their clothes felt even softer after coming out of the washing machine. It works this way: if you muffle the sound of your hands being rubbed together while you're rubbing them, your brain assumes that they must be smoother than they are. That's because your brain combines the audio information with the tactile sensation and assumes because there's less noise, there's less friction, and hence softer skin. This idea—that if you change the input in one sensory realm, you can influence perception in another—is called crossmodal sensory interaction, and it lies at the core of Spence's research.

    "Food and drink are among life's most multisensory experiences," Spence pointed out, so it's perhaps hardly surprising that it occurred to him that the parchment skin illusion might work in the mouth, using food rather than clothing. He recruited 200 volunteers willing to eat Pringles for science, and played them modified crunching sounds through headphones, some louder and some more muffled, as they ate. And he found that he could make a 15 percent difference in people's perception of a stale chip's freshness by playing them a louder crunch when they bit into it.

    "The party version" of this trick, according to Spence, was developed by colleagues in the Netherlands and Japan. Volunteers were asked to crunch on chips in time with a metronome, while researchers played crunching sounds back, in perfect synchrony, through their headphones. All was well until the researchers replaced the crunching with the sound of breaking glass—and "people's jaws just freeze up."

    Have a bag of chips that's been sitting around too long? Here's the sonic boost they need.

    And—thanks, science!—here's a soundtrack to make your perfectly fresh chips taste stale.

    As far as breaking glass goes, we can't condone inflicting that kind of trauma—you're on your own.

    HOT AND COLD

    Listen to this recording of two drinks being poured into a glass, back to back. Can you tell whether each drink was hot or cold? (Scroll down to the end of this section for the answers.)

    According to Spence, you should be able to guess. The human ear is sensitive enough to pick up on the slight change in a liquid's viscosity as it changes temperature. Hot water is less viscous than cold, which means that the splash it makes when it hits the bottom of the glass or mug is a tiny bit splashier—and thus higher pitched.

    This finding has practical applications in advertising, for example, as well as drinks dispensers—your soup or coffee could be made to seem piping hot, or your soda even more cool and refreshing. But Spence also suggests playing with it: blindfolding guests and handing them a cold drink while playing the sound of a hot one. The result? With the sound, "we've put the idea in your mind, the expectation that it's going to be very hot," he explains. "And then when you put it to your lips and it's suddenly cold, you'll be shocked, but you probably won't know quite why you should be shocked."

    (Answer: the first pour was cold, the second was hot.)

    BITTERSWEET SYMPHONY

    So far, we've focused on the sound that food makes, either in your mouth or in the glass. But Spence's recent research has focused on something much more abstract and mysterious: an implicit association between particular kinds of sound and tastes. The idea that different scents, tastes, and flavors might correspond to different musical notes has a long, if speculative, history: in nineteenth-century London, perfumer Septimus Piesse created a scent scale in which middle C was matched with rose, while an octave lower was geranium. In the following decades, novelists picked up on the idea and invented fictional liqueur flavor keyboards (Joris-Karl Huysman's Against Nature), a "pianocktail" machine (Boris Vian's L'Ecume des Jours), and a scent organ (Aldous Huxley's Brave New World).

    Pinaocktail
    On the left, a diagram of the pianocktail created by Florica Vlad; on the right, a mechanical version of the pianocktail built by musician Géraldine Schenkel.

    According to Spence, the first scientist to test the concept, however, was Kristian Holt-Hansen, working in Denmark. Using Carlsberg's lager and Elephant beer as his two test beverages, he demonstrated that people consistently matched a lower-pitched tone (510-520 Hz) to the lager, and a slightly higher note (640-670 Hz) to the more vinous Elephant beer. He then found that when he played the matching sound to people as they consumed the appropriate beer, they rated it as tasting better. As unlikely as it sounds, Canadian scientists successfully replicated the experiment in 1984, with the confusing addition of grapefruit and dill pickle, which matched even higher pitched sounds (1016 Hz and 1394 Hz, respectively).

    That was the state of the science when Charles Spence decided to test the connection between pitch and taste in 2012. Using a bittersweet toffee specially created by chef Heston Blumenthal, Spence and his colleagues showed that people perceived the toffee as ten percent more bitter while listening to low-pitched notes, and ten percent sweeter when their headphones were filled with higher-pitched music. Subsequently, Spence says he's tried this experiment on people from all over the world, and found a similar correspondence. You can try it at home with some bittersweet dark chocolate and these two soundtracks. The first one is sweet-enhancing, the second will boost bitter.


    But, although the effect is real, the mechanism behind it is more elusive. Listen to this episode of Gastropod to understand how and why sound affects our experience of food—and how we might use that science to redesign the experience of eating. From chefs playing with sonic seasoning to enhance our dinner, to the perfect soundtrack for whiskey, we explore the way our brains combine sound with our other senses to create flavor. This is the second in a two-part series exploring the relationship between sound and food: don't miss the previous episode of Gastropod for much more on the experimental history and emerging science of acoustic agriculture, from the perfect bovine playlist to the lost rhythms of Southern farming. And, if you like what you hear, please support our work with a donation of any size.

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  • Cocktail Hour

    The Secret Ingredient No Cocktail Should be Without

    It might seem counterintuitive, but, in a world overflowing with fancy bitters and spherical ice makers, the thing your cocktail is missing is actually much simpler: salt. Dave Arnold, the mixologist behind high-tech cocktail bar Booker and Dax, shared this secret with Gastropod. It's just one of several scientific tricks contained in his new book, Liquid Intelligence: The Art and Science of the Perfect Cocktail.

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  • Genetically-engineered yeast is the future of flavor

    Throughout human history, if you wanted to make a dish taste like strawberry, you had no choice but to add a strawberry. But in the 19th century, scientists began to understand how to synthesize flavor chemicals, whether from plants or from byproducts of coal processing, to evoke familiar flavors. While the technology to evaluate the flavor molecules of a particular food have become increasingly sophisticated in the past century, the basic concept of synthetic flavor has remained unchanged. Until now. In this episode of Gastropod, molecular biologists explain how they're designing yeasts to ferment the tastes of the future.

    Natural vs. Artificial

    Let's start with a graham cracker. Just like Sylvester Graham back in 1829, if you're baking at home, you'd probably use coarse-ground whole-wheat flour, wheat bran, and wheat germ. These, along with some honey for sweetness, would give your graham crackers their distinctive toasty, malty, and slightly nutty flavor. If you're making them by the billion, however, at a Nabisco or Keebler factory, the ingredients list looks a little different. That extra wheat germ and bran contain natural oils with a tendency to go rancid—but, when you cut them out to gain shelf-life, you lose the flavor.

    Fortunately, there's an easy solution: you can add all that flavor back with just a touch of a light yellow, crystalline powder called 2-acetylpyrazine. This is an aromatic, carbon-based chemical, known by flavorists as the "graham-cracker" flavor. It occurs naturally in nuts and toasted grains; as the vital ingredient giving factory-made graham crackers their signature flavor, it can either be extracted from a plant or synthesized using petrochemical derivatives.

    The major difference is that 2-acetylpyrazine produced by performing chemical reactions on plant matter costs about $25 per lb—compared to the $5 or $6 per lb it costs to produce the kind whose raw ingredients come in a drum.

    However, using the cheap version comes with another, increasingly significant cost: it means you have to include the words "artificial flavor" on your graham cracker ingredients list. Under FDA rules, if the raw material to make your flavor chemical comes from a plant, animal, or edible yeast, it's "natural," for the purposes of labeling. If it comes from anything else, it's artificial. And consumers increasingly don't want to buy things that are "artificial." In fact, Michelle Hagen, a senior flavorist at Givaudan, the world's largest fragrance and flavor company, told Gastropod that, despite the cost savings, she hasn't used a single artificial chemical in her flavorings for the past four years—because the soda companies she mostly works with know that customers are turned off when they see that word on a label.

    Enter the (Genetically Engineered) Yeast

    Until recently, the natural flavors that Hagen uses would, for the most part, have been extracted from a plant; a handful of rarer ingredients, more often used in perfumery, would have come from animal sources. Today, advances in genetic engineering, combined with the growing consumer demand for natural flavors, are creating an intriguing new option for the world's flavorists. In the past, the mention of "edible yeast" in the FDA definition of natural flavors typically referred to savory yeast extracts; now, designer yeasts are beginning to pump out vanilla, saffron, and even grapefruit flavors.

    ginkgo-test-99325cf5

    For this episode, Gastropod visited Ginkgo BioWorks, one of a new wave of companies redesigning yeasts to produce fragrance and flavor chemicals. As Christina Agapakis, a scientist, writer, and artist who recently joined Ginkgo's staff, explained, the biology behind genetically modifying microbes to produce other, useful chemicals is not new. More than three decades ago, in 1978, biotech companies successfully inserted genes into bacteria to produce human insulin, meaning that diabetics need no longer depend on a close-enough version extracted from pig pancreases. In 1990, the FDA approved rennet made by inserting cow genes into E. coli bacteria; today, more than 90 percent of all cheese in the U.S. and U.K. is made using this bio-engineered product, rather than natural rennet found in the stomach linings of calves.

    ginkgo-organism-design-184277f1

    What is new, Agapakis told Gastropod, is "the ability to create flavors." Rather than inserting the single gene that codes for the insulin protein, she explained, "to make a flavor, you might need five or ten different enzymes that are creating a whole pathway and are really shifting the metabolism of the yeast." Fitting all those genes together so that what works in a plant to produce flavor also works in a yeast cell is challenging. Ginkgo has been developing its first yeast-fermented ingredient—a rose oil for the fragrance industry—for a couple of years now.

    In fact, as organism designer Patrick Boyle explained, the main reason that the Ginkgo "foundry" is filled with liquid-handling robots and high-tech machines is to help him and his colleagues rapidly run through all the tweaked yeasts that don't work. "Failure is usually not very dramatic," he told Gastropod. "It's just that we end up with a yeast that looks a lot like the yeast we started with."

    Still, a Swiss company called Evolva has recently brought the first of these "cultured flavors" to market: vanillin, the main ingredient in the world's most popular flavor. Ginkgo's rose oil smells pretty sweet, and the Boston-based company has half a dozen more flavor ingredients in the pipeline. And scientists in Austria just announced that they have successfully tweaked yeast to produce the key flavor chemical in grapefruit.

    The Future of Flavor

    Redesigning yeast to create flavor molecules offers some potential benefits. For starters, fermentation requires none of the harsh chemicals that are often used to extract essential oils from plants or react with petrochemical precursors. Engineered yeast also offers the possibility of democratizing rare, expensive flavors, like saffron, and, Patrick Boyle points out, it can "relieve some of the supply issues that come from using really rare plants."

    But the main attraction of this new technology for food companies is that the resulting flavors can legally be labelled as "natural"—they are produced by a yeast, after all. What's more, because there is no yeast left in the final product, cultured flavors actually don't contain genetically modified organisms.

    Still, companies are nervous—Michelle Hagen at Givaudan told Gastropod that she hadn't worked with any of these cultured flavors yet, and both Nestlé and General Mills responded to pressure from Friends of the Earth by pledging not to use cultured vanillin. In a press release, Friends of the Earth argued that using yeast to produce vanillin would threaten the livelihood of vanilla bean farmers in Madagascar, as well as the continued existence of the rainforest in which the vanilla orchid grows. But, as Patrick Boyle pointed out, the world demand for vanillin far outstrips the quantity of vanilla beans grown each year, and the synthetic and real vanilla industries have already managed to co-exist for more than a century.

    Debates over natural vs. artificial aside, perhaps the most interesting aspect of these designer yeasts is the potential they offer for creating entirely new flavor experiences. For Christina Agapakis, the opportunity to learn more about the genes and pathways that plants use to express flavor will, she hopes, lead to productive collaborations with fruit and vegetable breeders—and increased deliciousness in the field as well as in the lab.

    Listen to this episode to understand how the flavor industry got started and how designer yeasts could one day allow us to get closer to the taste of extinct, long-forgotten species—or even a Paleo flavor palette of pre-domestication plants and animals.

  • Cheese is the chameleon of the food world

    Cheese is the chameleon of the food world, as well as one of its greatest delights. Fresh and light or funky and earthy, creamy and melty or crystalline and crumbly —no other food offers such a variety of flavors and textures.

    But cheese is not just a treat for the palate: its discovery changed the course of Western civilization, and, today, cheese rinds are helping scientists conduct cutting-edge research into microbial ecology. In this episode of Gastropod, we investigate cheese in all stinking glory, from ancient Mesopotamia to medieval France, from the origins of cheese factories and Velveeta to the growing artisanal cheese movement in the U.S. Along the way, we search for the answer to a surprisingly complex question: what is cheese? Join us as we bust cheese myths, solve cheese mysteries, and put together the ultimate cheese plate.

    The secret history of cheese, or, why the cheese origin story is a myth

    This is the story you'll often hear about how humans discovered cheese: one hot day nine thousand years ago, a nomad was on his travels, and brought along some milk in an animal stomach—a sort of proto-thermos—to have something to drink at the end of the day. But when he arrived, he discovered that the rennet in the stomach lining had curdled the milk, creating the first cheese. But there's a major problem with that story, as University of Vermont cheese scientist and historian Paul Kindstedt told Gastropod: the nomads living in the Fertile Crescent of the Middle East in 7000 B.C. would have been lactose-intolerant. A nomad on the road wouldn't have wanted to drink milk; it would have left him in severe gastro-intestinal distress.

    Kindstedt, author of the book Cheese and Culture, explained that about a thousand years before traces of cheese-making show up in the archaeological record, humans began growing crops. Those early fields of wheat and other grains attracted local wild sheep and goats, which provide milk for their young. Human babies are also perfectly adapted for milk. Early humans quickly made the connection and began dairying—but for the first thousand years, toddlers and babies were the only ones consuming the milk. Human adults were uniformly lactose-intolerant, says Kindstedt. What's more, he told us that "we know from some exciting archaeo-genetic and genomic modeling that the capacity to tolerate lactose into adulthood didn't develop until about 5500 BC"—which is at least a thousand years after the development of cheese.

    The real dawn of cheese came about 8,500 years ago, with two simultaneous developments in human history. First, by then, over-intensive agricultural practices had depleted the soil, leading to the first human-created environmental disaster. As a result, Neolithic humans began herding goats and sheep more intensely, as those animals could survive on marginal lands unfit for crops. And secondly, humans invented pottery: the original practical milk-collection containers.

    In the warm environment of the Fertile Crescent region, Kinstedt explained, any milk not used immediately and instead left to stand in those newly invented containers "would have very quickly, in a matter of hours, coagulated [due to the heat and the natural lactic acid bacteria in the milk]. And at some point, probably some adventurous adult tried some of the solid material and found that they could tolerate it a lot more of it than they could milk." That's because about 80 percent of the lactose drains off with the whey, leaving a digestible and, likely, rather delicious fresh cheese.

    Cheese changed the course of western civilization

    With the discovery of cheese, suddenly those early humans could add dairy to their diets. Cheese made an entirely new source of nutrients and calories available for adults, and, as a result, dairying took off in a major way. What this meant, says Kindstedt, is that "children and newborns would be exposed to milk frequently, which ultimately through random mutations selected for children who could tolerate lactose later into adulthood."

    In a very short time, at least in terms of human evolution—perhaps only a few thousand years—that mutation spread throughout the population of the Fertile Crescent. As those herders migrated to Europe and beyond, they carried this genetic mutation with them. According to Kindstedt, "It's an absolutely stunning example of a genetic selection occurring in an unbelievably short period of time in human development. It's really a wonder of the world, and it changed Western civilization forever."

    Tasting the first cheeses today

    In lieu of an actual time machine, Gastropod has another trick for listeners who want to know what cheese tasted like 9,000 years ago: head to the local grocery store and pick up some ricotta or goat's milk chevre. These cheeses are coagulated using heat and acid, rather than rennet, in much the same way as the very first cheeses. Based on the archaeological evidence of Neolithic pottery containers found in the Fertile Crescent, those early cheeses would have been made from goat's or sheep's milk, meaning that they likely would have been somewhat funkier than cow's milk ricotta, and perhaps of a looser, wetter consistency, more like cottage cheese.

    "It would have had a tart, clean flavor," says Kindstedt, "and it would have been even softer than the cheese you buy at the cheese shop. It would have been a tart, clean, acidic, very moist cheese."

    So, the next time you're eating a ricotta lasagne or cheesecake, just think: you're tasting something very similar to the cheese that gave ancient humans a dietary edge, nearly 9,000 years ago.

    Camembert used to be green

    Those early cheese-making peoples spread to Europe, but it wasn't until the Middle Ages that the wild diversity of cheeses we see today started to emerge. In the episode, we trace the emergence of Swiss cheese and French bloomy rind cheeses, like Brie. But here's a curious fact that didn't make it into the show: when Gastropod visited Tufts microbiologist Benjamin Wolfe in his cheese lab, he showed us a petri dish in which he was culturing the microbe used to make Camembert, Penicillium camemberti. And it was a gorgeous blue-green color.

    Wolfe explained that according to Camembert: A National Myth, a history of the iconic French cheese written by Pierre Boisard, the original Camembert cheeses in Normandy would have been that same color, their rinds entirely colonized by Wolfe's "green, minty, crazy" microbe. Indeed, in nineteenth-century newspapers, letters, and advertisements, Camembert cheeses are routinely described as green, green-blue, or greenish-grey. The pure white Camembert we know and love today did not become the norm until the 1920s and 30s. What happened, according to Wolfe, is that if you grow the wild microbe "in a very lush environment, like cheese is, it eventually starts to mutate. And along the way, these white mutants that look like the thing we think of as Camembert popped up."

    In his book, Boisard attributes the rapid rise of the white mutant to human selection, arguing that Louis Pasteur's discoveries in germ theory at the start of the twentieth-century led to a prejudice against the original "moldy"-looking green Camembert rinds, and a preference for the more hygienic-seeming pure white ones. Camembert's green origins have since been almost entirely forgotten, even by the most traditional cheese-makers.

    Camembert1

    Listen to this week's episode of Gastropod for much more on the secret history and science of cheese, including how early cheese bureaucracy led to the development of writing, what studying microbes in cheese rinds can tell us about microbial ecology in our guts, and why in the world American cheese is dyed orange. (Hint: the color was originally seen as a sign of high quality.) Plus, Gastropod will help you put together the world's most interesting cheese plate to wow guests at your next dinner party. Listen here for more!

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  • The most valuable semen in all the land

    In 1900, the average dairy cow in America produced 424 gallons of milk each year. By 2000, that figure had more than quadrupled, to 2,116 gallons. In this episode of Gastropod, we explore the incredible science that transformed the American cow into a milk machine — but we also uncover the disturbing history of prejudice and animal cruelty that accompanied it.

    Along the way, we'll introduce you to the insane logic of the Lifetime Cheese Merit algorithm and the surreal bull trials of the 1920s. This is the untold story behind that most wholesome and quotidian of beverages: milk. Prepare to be horrified and amazed in equal measure.

    New and Improved Bulls

    Something extremely bizarre took place in the early decades of the twentieth century, inspired by a confluence of trends. Scientists had recently developed a deeper understanding of genetics and inherited traits; at the same time, the very first eugenics policies were being enacted in the United States. And, as the population grew, the public wanted cheaper meat and milk. As a result, in the 1920s, the USDA encouraged rural communities around the U.S. to put bulls on the witness stand—to hold a legal trial, complete with lawyers and witnesses and a watching public—to determine whether the bull was fit to breed.

    Livestock breeding was a normal part of American life at the dawn of the twentieth century, according to historian Gabriel Rosenberg. The U.S., he told Gastropod, was "still largely a rural and agricultural society," and farm animals — and thus some more-or-less scientific forms of selective breeding — were ubiquitous in American life.

    Meanwhile, the eugenics movement was on the rise. Founded by Charles Darwin's cousin, Francis Galton, eugenics held that the human race could improve itself by guided evolution—which meant that criminals, the mentally ill, and others of "inferior stock" should not be allowed to procreate and pass on their defective genes. America led the way, passing the first eugenic policies in the world. By the Second World War, twenty-nine states had passed legislation that empowered officials to forcibly sterilize "unfit" individuals.

    A "Better Sires: Better Stock" accredited dairy herd.

    A "Better Sires: Better Stock" accredited dairy herd.

    Combine the growing population, the desire for cheap meat and milk, and the increasing popularity of eugenics, and the result, Rosenberg said, was the "Better Sires: Better Stock" program, launched by the USDA in 1919. In an accompanying essay, "Harnessing Heredity to Improve the Nation's Live Stock," the USDA's Bureau of Animal Industry proclaimed that, each year, "a round billion dollars is lost because heredity has been permitted to work with too little control." The implication: humans needed to take control—and stop letting inferior or "scrub" bulls reproduce!

    Hear Ye! Hear Ye! Welcome to the Court of Bovine Justice

    The "Better Sires: Better Stock" campaign included a variety of elements to encourage farmers to mate "purebred" rather than "scrub" or "degenerate" sires with their female animals. Anyone who pledged to only use purebred stock to expand their herd was awarded a handsome certificate. USDA field agents distributed pamphlets entitled "Runts and the Remedy" and "From Scrubs to Quality Stock," packed with charts showing incremental increases of dollar value with each improved generation as well as testimonials from enrolled farmers.

    Better Sires Better Stock certificate  The "Better Sires: Better Stock" certificate, awarded to farmers who pledged to use purebred rather than scrub bulls.

    Better Sires Better Stock certificate The "Better Sires: Better Stock" certificate, awarded to farmers who pledged to use purebred rather than scrub bulls.

    By far the most peculiar aspect of the campaign, however, came in 1924, when the USDA published its "Outline for Conducting a Scrub-Sire Trial." This mimeographed pamphlet contained detailed instructions on how to hold a legal trial of a non-purebred bull, in order to publicly condemn it as unfit to reproduce. The pamphlet calls for a cast of characters to include a judge, jury, attorneys, and witnesses for the prosecution and the defense, as well as a sheriff, who should "wear a large metal star and carry a gun," and whose role, given the trial's foregone conclusion, was "to have charge of the slaughter of the condemned scrub sire and to superintend the barbecue."

    In addition to an optional funeral oration for the scrub sire and detailed instructions regarding the barbecue or other refreshments ("bologna sandwiches, boiled wieners, or similar products related to bull meat" are recommended), the pamphlet also includes a script that begins with the immortal lines: "Hear ye! Hear ye! The honorable court of bovine justice of ___ County is now in session." The County's case against the scrub bull is laid out: that he is a thief for consuming "valuable provender" while providing no value in return, that he is an "unworthy father," and that his very existence is "detrimental to the progress and prosperity of the public at large." Several pages and roughly two hours later, the trial concludes with the following stage direction: "The bull is led away and a few moments later a shot is fired."

    Within a month of publication, the USDA reported receiving more than 500 requests for its scrub-sire trial pamphlets. Across the country, the court of bovine justice was convened at county fairs, cattle auctions, and regional farmers' association meetings, forming a popular and educational entertainment.

    Order of ProcedureThe Order of Procedure, from the USDA's "Outline for Conducting a Scrub-Sire Trial," 1924.

    The Genomic Bull

    These bull trials may seem like a forgotten, bizarre, and ultimately amusing quirk of history, but, as Rosenberg reminded Gastropod, "they are talking about a lot more than just cattle genetics here."

    Indeed, the very same year — 1924 — that the USDA published its "Outline for Conducting a Scrub-Sire Trial," the State of Virginia passed a Eugenical Sterilization Law. Immediately, Dr. Albert Sidney Priddy, Director of the Virginia State Colony for Epileptics and Feebleminded, filed a petition to sterilize Carrie Buck, an 18-year-old whom he claimed had a mental age of 9, and who had already given birth to a supposedly feeble-minded daughter (following a rape). Buck's case went all the way to the Supreme Court, with Justice Oliver Wendell Holmes, Jr., upholding the decision in a 1927 ruling that concluded: "Three generations of imbeciles are enough." Historians estimate that more than 60,000 Americans were sterilized in the decades leading up to the Second World War, with many more persecuted under racist immigration laws and marriage restrictions.

    The verdictThe verdict (a foregone conclusion), from the USDA's "Outline for Conducting a Scrub-Sire Trial," 1924.

    Eugenics, with its philosophical kinship to Nazism, largely fell out of favor in the U.S. by World War II. But the ideas promoted in the bull trials—that humans can and should take increasing control of animal genetics in order to design the perfect milk machine—have gained ground throughout the past century, as breeding has become ever more technologically advanced. As we discuss in this episode of Gastropod, the drive to improve dairy cattle through livestock breeding has led to huge innovations—in IVF, in genomics, and in big data analysis—as well as much more milk. But it has also continued, for better and for worse, to highlight the ethical problems that stem from this kind of techno-utopian approach to reproduction.

    In this episode of Gastropod, we find out about the bull trials of the 1920s and meet the most valuable bull in the world, as we explore the history and the high-tech genomic science behind livestock breeding today. Along the way, we tease out its larger, thought-provoking, and frequently deeply troubling implications for animal welfare and society in general. Listen now!

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  • Breakfast: the most important meal of the day?

    Much has been made about the importance of a good breakfast to a healthy lifestyle. It gives you energy to start your day, according to conventional wisdom, and scientific studies conducted a decade ago had proclaimed that eating breakfast was the key to maintaining a healthy weight.

    Breakfast skippers are plagued with well-meaning spouses, partners, family members, and friends, all insisting that they should eat something in the morning. But, according to nutrition scientist P. K. Newby, that advice was based on what's known as observational studies, in which scientists follow groups of people and observe the outcomes. The result had seemed to indicate that people who lost weight or maintained a healthy weight ate breakfast. The problem, Newby told us, is that those studies didn't isolate breakfast as the important factor. It could be, she says, that those who lost weight also exercised more, or one of dozens of other variables.

    Then, last year, a group of researchers at the University of Alabama published a study that took a more rigorous look at this question. They enlisted 300 participants and randomly assigned them to eat breakfast, to skip breakfast, or to simply go about their normal routine. After 16 weeks, they found no difference in weight loss among the three groups. Meanwhile, in a similarly controlled Cornell University study, people who skipped breakfast consumed fewer calories by the end of the day. And, in a smaller study at the University of Bath, people who skipped breakfast also seem to have consumed slightly fewer calories during the day, though they then expended slightly less energy.

    Based on this new research, the bottom line, Newby says, is this: if you're not hungry in the morning, there's no harm in skipping breakfast when it comes to weight management. "It's the what that is more important than the when, when it comes to breakfast," she says, which also means that grabbing a sugary muffin, doughnut, or other pastry, just to eat something in the morning, is a worse idea than eating nothing at all.

    QUESTIONING THE CULT OF JUICE

    It's January, and everybody on the Internet has embarked on a juice cleanse. But you don't have to feel guilty for sticking to solids: without the accompanying fiber in fruit, juice delivers a straight shot of sugar.

    Photography by Viktor Rosenfeld, used under a Creative Commons license.

    Photography by Viktor Rosenfeld, used under a Creative Commons license.

    Juice, like sugary cereals, muffins, and white bread, is "quickly metabolized," said Newby. "These foods lead to a spike in sugar and insulin, and then it dissipates. And so then, in a short period of time, you feel hungry again." That, she continues, can lead to overeating and weight gain. And there are long-term health consequences as well: she says diets high in refined carbohydrates are a risk factor for type 2 diabetes and cardiovascular disease.

    Newby says that the most important thing to understand about breakfast is that it's simply another meal. It may seem as though we should eat only breakfast foods—cereal, juice, bagels—at breakfast time, but, as historian Abigail Carroll explains during this episode of Gastropod, that's just a historical hangover from nineteenth-century American health reformers. And, as Newby points out, we already know what makes a healthy meal at any time of day: put vegetables at the center of the plate, accompanied by whole grains, beans, nuts, and healthy fats.

    THE FIRST CUP OF COFFEE

    Though Newby says that it's what you eat that matters, not when, that may not be the case when it comes to coffee. We spoke to neuroscience PhD candidate Steven Miller, studying at the Uniformed Services University of the Health Sciences, about chronopharmacology, or the science of how brain chemistry interacts with drugs, in order to learn how timing affects the most popular stimulant in the world: caffeine.

    Photograph by trophygeek, used under a Creative Commons license.

    Photograph by trophygeek, used under a Creative Commons license.

    Cortisol, the stress hormone that helps us feel alert and energized, peaks at about 8 or 9am, at least for people who work a typical 9-to-5 job and sleep during the same hours each night. Most people, says Miller, don't need caffeine to give them a boost at a time they're already naturally alert. In addition, drinking a caffeinated beverage at a time when you're already sharp could lead to desensitization, which, Miller explains, means that you'll need an increasing amount of the drug—in this case caffeine—to get the same effect.

    For the best morning buzz based on brain biology, Miller recommends saving your coffee fix until 9:30am, when cortisol levels are starting to drop off.

    He admits, though, that his recommendation doesn't hold true for everyone: anyone whose sleep schedule is not regular or who works evening or night shifts will have a different cortisol production rhythm. In fact, he actually doesn't follow his own chronopharmacological advice. Miller told Gastropod that, as a neuroscience PhD student, he works long, irregular hours and gets little sleep, and he always starts off his day, at any hour, with an extra strong caffeinated beverage.

    THE MOST CAPITALIST MEAL OF ALL

    Miller's decision to design his coffee routine around his work schedule, rather than biology, isn't surprising given the history of breakfast. As we learn from journalist Malia Wollan, while breakfast foods may be different all around the world, it's the first meal to change in immigrant households. And, as Three Squares author Abigail Carroll explains, those classic American breakfast foods can be traced directly back to the Industrial Revolution and its transformation of labor—combined with some entrepreneurial innovations in processing, packaging, and marketing that were first pioneered in breakfast cereal but went on to transform the American diet. To learn more about the revolutionary history, global peculiarities, and surprising science of breakfast, listen to our latest episode of Gastropod.

    About this episode of Gastropod: Armed with a healthy dose of caffeine chronopharmacology, we embark on a global breakfast tour that exposes the worldwide dominance of Nutella, as well as the toddler kimchi acclimatization process. Meanwhile, back in the U.S., we trace the American breakfast's evolution from a humble mash-up of leftover dinner foods to its eighteenth-century explosion into a feast of meats, griddle cakes, eel, and pie—followed swiftly by a national case of indigestion and a granola-fueled backlash. Breakfast has been a battleground ever since: in this episode, we not only explain why, but also serve up the best breakfast contemporary science can provide. See episode shownotes.

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