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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Win a Trip to Any National Park By Instagramming Your Travels
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If you're planning out your summer vacation, make sure to add a few national parks to your itinerary. Every time you share your travels on Instagram, you can increase your chances of winning a VIP trip for two to the national park of your choice.

The National Park Foundation is hosting its "Pic Your Park" sweepstakes now through September 28. To participate, post your selfies from visits to National Park System (NPS) properties on Instagram using the hashtag #PicYourParkContest and a geotag of the location. Making the trek to multiple parks increases your points, with less-visited parks in the system having the highest value. During certain months, the point values of some sites are doubled. You can find a list of participating properties and a schedule of boost periods here.

Following the contest run, the National Park Foundation will decide a winner based on most points earned. The grand prize is a three-day, two-night trip for the winner and a guest to any NPS property within the contiguous U.S. Round-trip airfare and hotel lodging are included. The reward also comes with a 30-day lease of a car from Subaru, the contest's sponsor.

The contest is already underway, with a leader board on the website keeping track of the competition. If you're looking to catch up, this national parks road trip route isn't a bad place to start.

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15 Dad Facts for Father's Day
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Gather 'round the grill and toast Dad for Father's Day—the national holiday so awesome that Americans have celebrated it for more than a century. Here are 15 Dad facts you can wow him with today.

1. Halsey Taylor invented the drinking fountain in 1912 as a tribute to his father, who succumbed to typhoid fever after drinking from a contaminated public water supply in 1896.

2. George Washington, the celebrated father of our country, had no children of his own. A 2004 study suggested that a type of tuberculosis that Washington contracted in childhood may have rendered him sterile. He did adopt the two children from Martha Custis's first marriage.

3. In Thailand, the king's birthday also serves as National Father's Day. The celebration includes fireworks, speeches, and acts of charity and honor—the most distinct being the donation of blood and the liberation of captive animals.

4. In 1950, after a Washington Post music critic gave Harry Truman's daughter Margaret's concert a negative review, the president came out swinging: "Some day I hope to meet you," he wrote. "When that happens you'll need a new nose, a lot of beefsteak for black eyes, and perhaps a supporter below!"

5. A.A. Milne created Winnie the Pooh for his son, Christopher Robin. Pooh was based on Robin's teddy bear, Edward, a gift Christopher had received for his first birthday, and on their father/son visits to the London Zoo, where the bear named Winnie was Christopher's favorite. Pooh comes from the name of Christopher's pet swan.

6. Kurt Vonnegut was (for a short time) Geraldo Rivera's father-in-law. Rivera's marriage to Edith Vonnegut ended in 1974 because of his womanizing. Her ever-protective father was quoted as saying, "If I see Gerry again, I'll spit in his face." He also included an unflattering character named Jerry Rivers (a chauffeur) in a few of his books.

7. Andre Agassi's father represented Iran in the 1948 and 1952 Olympics as a boxer.

8. Charlemagne, the 8th-century king of the Franks, united much of Western Europe through military campaigns and has been called the "king and father of Europe" [PDF]. Charlemagne was also a devoted dad to about 18 children, and today, most Europeans may be able to claim Charlemagne as their ancestor.

9. The voice of Papa Smurf, Don Messick, also provided the voice of Scooby-Doo, Ranger Smith on Yogi Bear, and Astro and RUDI on The Jetsons.

10. In 2001, Yuri Usachev, cosmonaut and commander of the International Space Station, received a talking picture frame from his 12-year-old daughter while in orbit. The gift was made possible by RadioShack, which filmed the presentation of the gift for a TV commercial.

11. The only father-daughter collaboration to hit the top spot on the Billboard pop music chart was the 1967 hit single "Something Stupid" by Frank & Nancy Sinatra.

12. In the underwater world of the seahorse, it's the male that gets to carry the eggs and birth the babies.

13. If show creator/producer Sherwood Schwartz had gotten his way, Gene Hackman would have portrayed the role of father Mike Brady on The Brady Bunch.

14. The Stevie Wonder song "Isn't She Lovely" is about his newborn daughter, Aisha. If you listen closely, you can hear Aisha crying during the song.

15. Dick Hoyt has pushed and pulled his son Rick, who has cerebral palsy, through hundreds of marathons and triathlons. Rick cannot speak, but using a custom-designed computer he has been able to communicate. They ran their first five-mile race together when Rick was in high school. When they were done, Rick sent his father this message: "Dad, when we were running, it felt like I wasn't disabled anymore!"

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