Blaming the main course, turkey, for causing sleepiness is a common Thanksgiving misconception. It is true that turkey contains an amino acid called tryptophan, a precursor to melatonin. The neurotransmitter serotonin is generated from tryptophan and can cause drowsiness, and this is where many just accept turkey being the sole reason for their nap.

However, even though turkey is a great supplier of tryptophan, other meat products have almost the same amount. While you consume turkey, there are also several other amino acids entering in your bloodstream. Tryptophan being the smallest compared to all the others, causing it to have no impact.

So if turkey is not the culprit, what is?

According to neuropharmacologist Richard Wurtman of Massachusetts Institute of Technology’s Department of Brain and Cognitive Sciences in Cambridge, Mass., eating turkey then dessert can cause drowsiness. Sugary desserts cause beta cells to activate insulin in the pancreas. Insulin takes out tryptophan’s competitors in the turkey, allowing tryptophan to reach the brain, causing you to feel sleepy. 

Gorging on large quantities of food also causes tiredness. According to biologist H. Craig Heller at Stanford University in Palo Alto, California: “There is a general phenomenon of parasympathetic tone – rest and digest – that is conducive to sleep.” 

Avoid stressful topics like discussing the pandemic or election results during Thanksgiving – bring up this interesting topic instead.