Does Turkey Make You Sleepy by Lorne Epstein

These are the mashed potatoes I made for today's (11/27/2025) Thanksgiving dinner

At Thanksgiving tables around the country, someone is going to point to the turkey and say:

“The tryptophan will knock you out!”

That’s not quite accurate.

Turkey does contain tryptophan. But foods like eggs, seeds, and cheese contain similar or even higher amounts. So why do so many people feel tired after a big holiday meal?

Yes, tryptophan plays a role; however, the driver is carbohydrates.

When we eat a large, carb-heavy meal, the pancreas releases insulin, which clears other amino acids from the bloodstream. That gives tryptophan a clear path into the brain, where it converts into serotonin, the neurotransmitter linked to calmness and rest.

Later, serotonin is used to produce melatonin, the hormone that helps us fall asleep. For me, as a neuroscience graduate student, this is where it gets interesting…

Serotonin also influences how we make decisions.

For my master’s research at George Mason University, I plan to conduct a human experiment to examine how reducing tryptophan levels affects decision-making traits, such as risk-taking, impulse control, and cognitive flexibility.

My research question: How does reducing tryptophan (and therefore serotonin) influence a leader’s decision-making?

I look forward to learning and discovering clues about how humans make decisions. Follow my research here https://www.lorneepstein.com/blog-1