Chemical Misconceptions: The Truth About Turkey...

As we get closer to Thanksgiving, I am reminded of an argument I had with a friend years ago as to the contribution of turkey - more specifically, the amino acid L-Tryptophan - on our typical feelings of lethargy and sleepiness after the big Thanksgiving meal.  I wrote this post way back then, and I thought I'd re-post it now (t'is the season).  I would encourage all of you who read it to spread the truth.  When someone blames the poor turkey for your sluggishness, stand up (stagger to your feet) and say, "It's not the turkey!".  Perhaps, together, we can make the world a happier, more informed place!

The Original Post (my new additions are in purple):

OK, I'm getting tired of having to explain this to people every time Thanksgiving rolls around. I'm not sure how these myths get started, or what perpetuates them, but nothing irritates me more than bad science. So I decided to post this to set the record straight.

First, the facts about L-Tryptophan. Tryptophan is an essential amino acid in your diet. That means your body can't make it by itself - you have to eat it. One of the uses of L-Tryptophan is in the production of Serotonin, a neurotransmitter in the brain. Serotonin is partly responsible for creating a relaxed, sleepy effect. So, since meats like turkey contain L-Tryptophan, shouldn't it make you sleepy when you eat lots of turkey?

In short, no. In order to become sleepy from L-Tryptophan, it would have to be the only thing in your stomach, and that means no other proteins present (never mind carbohydrates). Since few people actually eat pure L-Tryptophan, and since turkey meat is almost entirely protein, you can't get the serotonin spike just by eating turkey meat. In addition, the levels of Tryptophan in turkey are not much higher than the levels in other meats.  So what's the real story? Why do we get all befuddled after Thanksgiving dinner?

The real reason lies in the enormous amounts of carbohydrates and other food that we eat on Thanksgiving (or any holiday where food plays a central role). The large amounts of carbs in your belly diverts blood from your brain to your digestive tract, causing you to become sleepy (why do you think that most predators rest after they eat? It's so they can effectively digest.). Your digestive system works best when there is lots of blood supply in the area to cart away nutrients. The decreased blood flow in your brain deprives the brain of glucose, which in turn makes you a bit sleepy. Add to that the effects of alcohol (a depressant), and the glucose/insulin effect, and you've got nap time!  There is a psychological component to this as well.  Since holidays are typically times of relaxation (unless you're a member of a big Italian family that argues a lot, *cough, cough*), and because the most relaxing time of the actual day is usually meal time, your brain is more predisposed to feeling relaxed.  This feeling can persist even after the meal is over.

So, let's stop perpetuating bad science! Next time someone tells you that it's L-Tryptophan that makes you drowsy on Thanksgiving, offer this experiment. Challenge them to skip the turkey and eat only the other stuff and see if they're wide awake afterwards. Now, if you'll excuse me, I have to go eat.

The Fun Equation Revisited

Author's Note: This is a re-posting of an article I wrote a few years ago.  The blog in which I wrote the original is now defunct, but I loved this little piece, so I'm re-publishing it.

When I was in college, one of my best friends introduced me to the idea of The Fun Equation. Being both chemistry students, we often found humor in relating math and science to the 'real' world (whatever that is). The Fun Equation was a cute, funny, and fun way of looking at what makes an experience "fun".

Here's the equation in its most modern form. In order to really understand how fun is to be had, we first need to define our variables.

• F is, of course, Fun. The amount of fun to be had.
• M is Mess. Mess may be made by the person having fun, or be a result of the fun.
• N is Noise.
• Cp is the Potential for Getting Caught (but not actually getting caught - think of it as risk)
• S is Sleep.
• Is and Io are Injury terms. Is is Injury to Self, while Io is Injury to Others.
• Dp is Damage to Property, either belonging to self or others.
• Ca is Actually Getting Caught.

From the equation, we can see that Fun is compounding exponentially with respect to Mess, Noise, and the Potential for Getting Caught. Obviously, we'll want to maximize these to ensure that maximum fun is had by all. Experimental evidence for the dependence on Mess can be seen in the aftermath of any gathering (and I've had to clean up after my share). The Noise factor is usually observable during the event. The correlation with Potential for Getting Caught is only palpable if one is in attendance ("Quiet guys! The RA is coming!"). These relationships are clearly seen in the typical college party (which are arguably among the most fun).


The compound growth of Fun is offset by Sleep and Injury (both to self and others). Sleep, of course, removes us from the event (anecdotal effects of pranks perpetuated on the sleeping have been ignored). The sum of the Injury terms is squared due to the serious nature of injury. As injuries become more severe, they will naturally have more of a dampening effect on Fun. It should be noted that minor injuries do not often decrease fun to a noticeable degree, and there has been some evidence that, in the moment, these can actually increase Fun, although more research is needed in this area.


From the main expression, we must subtract the effects of Damage to Property and the square of whether or not we Actually Get Caught. Severe property damage subtracts a significant amount of Fun, and Actually Getting Caught (which is squared), can actually result in a negative value for Fun. Clearly, lack of permanent damage and avoiding getting caught eliminate this term from the equation. The balance between the Potential for Getting Caught and Actually Getting Caught is still being studied, and may result in a separate relationship that may need to be considered.


This version of The Fun Equation seems to be most appropriate to younger people. I am currently working on the Grown-Up Fun Equation, and will post this when suitable and sufficient testing has been completed. Variables such as Cost, Fatigue, and Good TV, are in contention for inclusion, but I am open to suggestions from my readers. Leave your ideas in the Comments.