It’s about the gobbler, but not the one you might think.
It has become a truism: You get sleepy at Thanksgiving because of all that
tryptophan in turkey. But is it true? Yes and no, but mostly no.
It is true that the amino acid tryptophan works as a precursor to other sleep-inducing chemicals. Turkey has lots of it. But cheese and nuts have more. Even Tofu-turkey has more, according to Wired.com.
In 1972 a psychiatrist named John Fernstrom looked into the tryptophan
connection and found that tryptophan alone does not make you sleepy. Instead, he found that it’s really a carb-heavy meal of mashed potatoes, pie, dressing, and bread. Those carbs create loads of sugar and force amino acids to go to work breaking it all down. With amino acids busy fighting sugars, the brain starts converting tryptophan into serotonin and suddenly you feel you just can’t watch another third and 10
on the game. Snores ensue.
It’s not just the chemistry of the meal, however. The parasympathetic nervous
system also has a role to play. This little brain gadget does things in the
background so you don’t think about them; like breathing. When you eat too much, you have to digest a lot. The parasympathetic nervous system kicks in to give the body energy to digest and takes away energy elsewhere. You feel tired and it’s because you ate a really big carb-loaded meal. Too late to do anything about it. Just kick off your
shoes and don’t blame the turkey.