It has happened to all of us... Dad doesn't know when to stop carving turkey. Mom insists we eat more of her sweet potato casserole. Grandma guilts us into a second helping of pie. And inevitably, we find ourselves passed out on the sofa after Thanksgiving dinner.
Most people blame the turkey for the sleepiness. It's popular wisdom to blame the tryptophan (pronounced trip-TO-fan), an essential amino acid found in turkey.