The Museum of Hoaxes
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Paul Krassner's Stereophonic Hoax, 1960
Can a bar of soap between your sheets ease muscle cramps?
The Diaphote, a television hoax, 1880
The damp spot that hoaxed a city, 1912
The Nazi Air Marker Hoax, 1942
Pierre Brassau, Monkey Artist, 1964
The Great Wall of China Hoax, 1899
Brief History of Triple-Decker Buses
Snowball the Monster Cat, 2000
The most sacred relic: the Holy Foreskin, circa 800 AD
The Turkey-Tryptophan Myth, and why do big meals make you drowsy?
Thanksgiving is approaching, which means the "turkey makes you tired because it has high levels of tryptophan" urban legend shall once again be heard at tables throughout America. Baylor College of Medicine dietitian Rebecca Reeves debunks this legend in an interview with the Houston Chronicle:

Q: So the tryptophan in turkey doesn't make you sleepy, right?

A: I am not sure how (that) gained wide acceptance. The urban legend is that the tryptophan in turkey is what makes you sleepy on Thanksgiving. Yes, the amino acid tryptophan is present in turkey, and in certain doses it can make you sleepy. But in reality, you'd need to eat an entire 40-pound turkey to get enough tryptophan to make a difference.

But her explanation of why people actually get tired after Thanksgiving dinner raises more questions in my mind than it answers:

Q: So why do people take a nap on the couch?

A: It's probably more due to alcohol. Or it could be that you got up that morning early to travel. Or it's been a long, beautiful day, and you're just tired. I hate to even mention this, but I've seen claims that because you're increasing your carbohydrates, you're increasing your blood sugar, maybe this could lead to sleepiness. But I'm not sure I agree with that.

Why is she doubtful that increasing carbohydrates (and thereby increasing blood sugar) can make you tired? She doesn't offer an explanation. Wikipedia offers a good summary of the "increased carbohydrates makes you tired" theory, and it sounds reasonable to me (more reasonable than the theory that the drowsiness is all due to having had a few beers, or the fact that it's been "a long, beautiful day"):

It has been demonstrated in both animal models and in humans that ingestion of a meal rich in carbohydrates triggers release of insulin. Insulin in turn stimulates the uptake of large neutral branched-chain amino acids (LNAA) but not tryptophan (trp) into muscle, increasing the ratio of trp to LNAA in the blood stream. The resulting increased ratio of tryptophan to large neutral amino acids in the blood reduces competition at the large neutral amino acid transporter resulting in the uptake of tryptophan across the blood-brain barrier into the central nervous system (CNS). Once inside the CNS, tryptophan is converted into serotonin in the raphe nuclei by the normal enzymatic pathway. The resultant serotonin is further metabolised into melatonin by the pineal gland. Hence, these data suggest that "feast-induced drowsiness," and in particular, the common post-Christmas and American post-Thanksgiving dinner drowsiness, may be the result of a heavy meal rich in carbohydrates which, via an indirect mechanism, increases the production of sleep-promoting melatonin in the brain.
Categories: Food, Science, Urban Legends
Posted by The Curator on Sun Nov 23, 2008
Comments (12)
There is a simpler answer that I have heard. The reason that people get sleepy is because they generally overeat. The overeating causes more blood to travel to the stomach to aid in digestion. Thereby, reducing oxygen to the brain and causing us to get drowsy.
Posted by Peter  in  Naugatuck, CT  on  Sun Nov 23, 2008  at  06:56 PM
Overeating will definitely cause drowsiness. The stomach uses a lot of energy in digesting food - particularly rich foods; that's why (a) invalids need "light" foods that are more easily digestible, and (b) someone badly injured or in shock may feel nauseous and want to vomit - it's the body's way of abandoning a job that it can't now spare the energy for.
Posted by Wendy Collings  in  Wellington, NZ  on  Sun Nov 23, 2008  at  10:42 PM
Back when I was learning for my master's degree, I used to take dextrose candy to keep me going. Too many of those and you get so tired you can hardly rise from your chair. Well known fact among students.
Posted by nasobem  in  Switzerland  on  Mon Nov 24, 2008  at  02:39 AM
"... But in reality, you'd need to eat an entire 40-pound turkey to get enough tryptophan to make a difference."

So who says I don't?
Posted by Big Gary  in  Turkey, Texas  on  Mon Nov 24, 2008  at  08:07 AM
Alex, I'm with you in not buying any of Ms. Reeves's theories.
I never drink alcohol at lunch; nonetheless eating a big lunch makes me sleepy in the afternoon.
And Thanksgiving is no more tiring than other days for me.

So I'm going with the insulin/melatonin idea.
Posted by Big Gary  in  Turkey, Texas  on  Mon Nov 24, 2008  at  08:11 AM
I get very sleepy around 3 or 4 in the afternoon. Unfortunately, I tend to get wide awake around 11 pm. I attribute it to aging.
Posted by Joe  on  Mon Nov 24, 2008  at  01:03 PM
Does anyone really get more tired after Thanksgiving dinner than after other large meals during the day? Or even small meals? Do people at large snooze more Thanksgiving afternoon than Sunday afternoon?

(That aside, my problem with the carbohydrate theory is that most the Thanksgiving dinners my wife and I make [or I've gone to when younger] are much higher in proteins and fats than a normal large meal.)
Posted by Joe  on  Mon Nov 24, 2008  at  01:07 PM
Peter, you are correct IMHO. Overeating. Yum yum.
Posted by Charles  in  Michigan  on  Mon Nov 24, 2008  at  04:04 PM
For a scientific hoax in this direction, see
"Trust and gullibility in science", by Tom Blundell
Trends in Biochemical Sciences
Volume 7, Issue 10, October 1982, Pages 352-353

To summarize:
A scientist was asked to give the final talk at a conference. Since in earlier years, it had become customary to end the conference with a somewhat less than serious talk, our scientist volunteered to give a "fun talk" and made up a story about the discovery of a novel, insulin related hormone called "sleepin", in analogy to another member of the insulin family, relaxin. This hormone was supposed to be involved in sleep regulation. After a rich meal, excess insulin was supposed to seep across the blood-brain barrier, cross-react with the receptor for this new hormone, and therefore induce the well-known phenomenon of sleepiness after eating and drinking. The talk was peppered with slides showing the structures of completely unrelated proteins.
The scientist was rather embarrassed when everybody took his talk at face value, and nobody in the audience challenged his presentation. He eventually had to interrupt the chairman to tell the audience that the subject of his talk was made up and had no foundation in reality.
Posted by Anaglyph  on  Tue Nov 25, 2008  at  01:09 PM
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Posted by raf  in  I like your blog  on  Mon Jan 10, 2011  at  09:15 AM
To summarize:
A scientist was asked to give the final talk at a conference. Since in earlier years, it had become customary to end the conference with a somewhat less than serious talk, our scientist volunteered to give a "fun talk" and made up a story about the discovery of a novel, insulin related hormone called "sleepin", in analogy to another member of the insulin family, relaxin. This hormone was supposed to be involved in sleep regulation. After a rich meal, excess insulin was supposed to seep across the blood-brain barrier, cross-react with the receptor for this new hormone, and therefore induce the well-known phenomenon of sleepiness after eating and drinking. The talk was peppered with slides showing the structures of completely unrelated proteins.
The scientist was rather embarrassed when everybody took his talk at face value, and nobody in the audience challenged his presentation. He eventually had to interrupt the chairman to tell the audience that the subject of his talk was made up and had no foundation in reality.
Posted by dolmuĊŸ reklam  on  Tue Jul 12, 2011  at  04:34 AM
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