Yes, it’s turkey season, the time of year when amateur nutritionists let us know that the feeling of sleepiness that we get after a huge turkey dinner is due to the amount of tryptophan in Ben Franklin’s favorite bird.
But how many can tell us what tryptophan actually is and what it actually does?
Tryptophan is an an essential amino acid that functions as a biochemical precursor (meaning it helps creates proteins in the body) for serotonin, niacin, and auxin.
The problem for the amateur nutritionists is twofold. One, the amount of tryptophan in turkey is comparable to that of beef and chicken, and is less than the amount found in soy beans and Parmesan cheese. Second, the situation/environment one would need to in order to fall asleep by consuming enough turkey is difficult to replicate on Thanksgiving day.
So why does it seem we fall asleep after a big meal on the day of Thanks? There’s actually a name for this – Post-prandial somnolence, which is a fancy way of saying “sleeping after eating”.
Look towards the amount of carbohydrates. They tend to have a high glycemic index, and when consumed in mass quantities (say, in dressing, gravy, mashed potatoes, and pumpkin pie), they tend to affect our insulin levels, pushing us towards a level of drowsiness.
So while tryptophan can make us sleepy, we actually create a more effective situation for sleepiness by eating a carb-heavy meal.
So, now you have just enough information to annoy your family on Thanksgiving day.