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Why Does Turkey Make Me Tired? What Makes Dark Meat Dark?

Why does turkey make me tired?

Most people blame tryptophan, but that's not really the main culprit. In case you're wondering, tryptophan is an amino acid that the body uses in the processes of making vitamin B3 and serotonin, a neurotransmitter that helps regulate sleep. It can't be produced by our bodies, so we need to get it through our diet. From which foods, exactly? Turkey, of course, but also other meats, chocolate, bananas, mangoes, dairy products, eggs, chickpeas, peanuts and a slew of other foods. Some of these, like cheddar cheese, have more tryptophan per gram than turkey. Tryptophan doesn't have much of an impact unless it's taken on an empty stomach and in an amount larger than what we're getting from our drumstick. So why does turkey get the rap as a one-way ticket to a nap?

The urge to snooze is more the fault of the average Thanksgiving meal and all the food and booze that go with it. Here are a few things that play into the nap factor:

Fats "“ That turkey skin is delicious, but fats take a lot of energy to digest, so the body redirects blood to the digestive system. Reduced blood flow in the rest of the body means reduced energy.

Alcohol "“ What Homer Simpson called the cause of—and solution to—all of life's problems is also a central nervous system depressant.

Overeating "“ Same deal as fats. It takes a lot of energy to digest a big feast (the average Thanksgiving meal contains 3,000 calories and 229 grams of fat), so blood is sent to the digestive process system, leaving the brain a little tired.

Why is dark meat dark and white meat white?

Among the many things inside our bodies (guts, black stuff, about fifty Slim Jims), there are two types of muscle fiber: fast twitch and slow twitch. Fast twitch muscle fibers, which contract quickly but consume a lot of energy and fatigue quickly, are used for rapid movements like jumping and sprinting. Slow twitch muscle fibers contract slowly but don't use much energy, and can contract for a long time before fatiguing; they're used for endurance activities.

Most of our muscles are made up of a mix of both slow and fast twitch fibers and, overall, the average human body has about a 50/50 mix of the two. Some people may have a higher percentage of one type or the other from developing those fibers through training and exercise. Some Olympic sprinters have as much as 80% fast twitch fibers and long-distance runners have the same percentage of slow-twitch. Ongoing research says that training can only alter the ratio so much, though. It seems that there's a genetic predisposition for having more of one fiber than another. But let's talk turkey.

The meat we eat from a turkey is turkey muscle, and turkeys have fast and slow twitch muscle fibers, too—though not in the same even mixing we see in humans. The difference between dark meat and white meat is due to the type of muscle fiber that's predominant in the meat and the way that fiber makes energy.

The muscles in turkey legs "“ the dark meat from the thighs and drumsticks "“ are mainly made up of slow twitch fibers, which get their energy from oxygen stored in the fibers by a protein called myoglobin. Myoglobin is a richly pigmented protein, and the more myoglobin there is in the fibers, the darker the meat.

Turkey wings and breasts, the white meat, are mostly made up of fast twitch muscle fibers, which get their energy from glycogen, a polysaccharide of glucose that's stored in the muscle fibers and doesn't have much pigment.

If you've eaten duck breast, you know that it's hardly what you'd call white meat. That's because unlike flightless turkeys, ducks take to the air a lot and have more slow twitch fibers, and more myoglobin, in their wings and breasts.

Thanksgiving by the Numbers

Before we all find a comfortable spot on the couch to curl up in, let's crunch some big numbers that go along with the big meal.

271 million - The estimated number of turkeys raised in the US this year. Of those, 49 million were raised in Minnesota, the leading turkey production state for the year.

$4.3 billion "“ The estimated amount that farmers will make from the sale of all those turkeys.

cranberries-istock.jpg3 "“ The number of places in the US that share a name with the bird. Turkey, Texas, was the most populous in 2007, with 465 residents.

689 million pounds "“ The estimate for US cranberry production this year. Wisconsin comes out on top with 385 million pounds produced.

1.8 billion pounds "“ The total weight of sweet potatoes produced by the major sweet potato producing states last year.

1.1 billion pounds "“ The total weight of the pumpkins produced last year by major pumpkin-producing states, with a value of $117 million. Illinois wiped the floor with the rest of the states' pumpkin patches and led the country with 542 million pounds worth of gourd.

177 million pounds "“ The tart cherry production for 2008, if pumpkin pie isn't your thing.

13.3 pounds "“ The amount of turkey that the average American ate in 2006.

(If you're a numbers geek, these figures came from the USDA National Agricultural Statistics Service, the USDA Economic Research Service and the Census Bureau, all of which have plenty of other fun stats to play with.)

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Big Questions
Why Does Turkey Make You Tired?
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iStock

Why do people have such a hard time staying awake after Thanksgiving dinner? Most people blame tryptophan, but that's not really the main culprit. And what is tryptophan, anyway?

Tryptophan is an amino acid that the body uses in the processes of making vitamin B3 and serotonin, a neurotransmitter that helps regulate sleep. It can't be produced by our bodies, so we need to get it through our diet. From which foods, exactly? Turkey, of course, but also other meats, chocolate, bananas, mangoes, dairy products, eggs, chickpeas, peanuts, and a slew of other foods. Some of these foods, like cheddar cheese, have more tryptophan per gram than turkey. Tryptophan doesn't have much of an impact unless it's taken on an empty stomach and in an amount larger than what we're getting from our drumstick. So why does turkey get the rap as a one-way ticket to a nap?

The urge to snooze is more the fault of the average Thanksgiving meal and all the food and booze that go with it. Here are a few things that play into the nap factor:

Fats: That turkey skin is delicious, but fats take a lot of energy to digest, so the body redirects blood to the digestive system. Reduced blood flow in the rest of the body means reduced energy.

Alcohol: What Homer Simpson called the cause of—and solution to—all of life's problems is also a central nervous system depressant.

Overeating: Same deal as fats. It takes a lot of energy to digest a big feast (the average Thanksgiving meal contains 3000 calories and 229 grams of fat), so blood is sent to the digestive process system, leaving the brain a little tired.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Space
More Details Emerge About 'Oumuamua, Earth's First-Recorded Interstellar Visitor
 NASA/JPL-Caltech
NASA/JPL-Caltech

In October, scientists using the University of Hawaii's Pan-STARRS 1 telescope sighted something extraordinary: Earth's first confirmed interstellar visitor. Originally called A/2017 U1, the once-mysterious object has a new name—'Oumuamua, according to Scientific American—and researchers continue to learn more about its physical properties. Now, a team from the University of Hawaii's Institute of Astronomy has published a detailed report of what they know so far in Nature.

Fittingly, "'Oumuamua" is Hawaiian for "a messenger from afar arriving first." 'Oumuamua's astronomical designation is 1I/2017 U1. The "I" in 1I/2017 stands for "interstellar." Until now, objects similar to 'Oumuamua were always given "C" and "A" names, which stand for either comet or asteroid. New observations have researchers concluding that 'Oumuamua is unusual for more than its far-flung origins.

It's a cigar-shaped object 10 times longer than it is wide, stretching to a half-mile long. It's also reddish in color, and is similar in some ways to some asteroids in own solar system, the BBC reports. But it's much faster, zipping through our system, and has a totally different orbit from any of those objects.

After initial indecision about whether the object was a comet or an asteroid, the researchers now believe it's an asteroid. Long ago, it might have hurtled from an unknown star system into our own.

'Oumuamua may provide astronomers with new insights into how stars and planets form. The 750,000 asteroids we know of are leftovers from the formation of our solar system, trapped by the Sun's gravity. But what if, billions of years ago, other objects escaped? 'Oumuamua shows us that it's possible; perhaps there are bits and pieces from the early years of our solar system currently visiting other stars.

The researchers say it's surprising that 'Oumuamua is an asteroid instead of a comet, given that in the Oort Cloud—an icy bubble of debris thought to surround our solar system—comets are predicted to outnumber asteroids 200 to 1 and perhaps even as high as 10,000 to 1. If our own solar system is any indication, it's more likely that a comet would take off before an asteroid would.

So where did 'Oumuamua come from? That's still unknown. It's possible it could've been bumped into our realm by a close encounter with a planet—either a smaller, nearby one, or a larger, farther one. If that's the case, the planet remains to be discovered. They believe it's more likely that 'Oumuamua was ejected from a young stellar system, location unknown. And yet, they write, "the possibility that 'Oumuamua has been orbiting the galaxy for billions of years cannot be ruled out."

As for where it's headed, The Atlantic's Marina Koren notes, "It will pass the orbit of Jupiter next May, then Neptune in 2022, and Pluto in 2024. By 2025, it will coast beyond the outer edge of the Kuiper Belt, a field of icy and rocky objects."

Last week, University of Wisconsin–Madison astronomer Ralf Kotulla and scientists from UCLA and the National Optical Astronomy Observatory (NOAO) used the WIYN Telescope on Kitt Peak, Arizona, to take some of the first pictures of 'Oumuamua. You can check them out below.

Images of an interloper from beyond the solar system — an asteroid or a comet — were captured on Oct. 27 by the 3.5-meter WIYN Telescope on Kitt Peak, Ariz.
Images of 'Oumuamua—an asteroid or a comet—were captured on October 27.
WIYN OBSERVATORY/RALF KOTULLA

U1 spotted whizzing through the Solar System in images taken with the WIYN telescope. The faint streaks are background stars. The green circles highlight the position of U1 in each image. In these images U1 is about 10 million times fainter than the faint
The green circles highlight the position of U1 in each image against faint streaks of background stars. In these images, U1 is about 10 million times fainter than the faintest visible stars.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Color image of U1, compiled from observations taken through filters centered at 4750A, 6250A, and 7500A.
Color image of U1.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Editor's note: This story has been updated.

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