“Eating turkey makes you sleepy.”

Many people associate the post (Review)-holiday meal slump directly with the turkey consumed, believing that this festive fowl possesses a unique ability to induce drowsiness. This popular idea stems from turkey's tryptophan content, an amino acid that the body uses to produce serotonin, which in turn can be converted into melatonin, a hormone known to regulate sleep. This chain of biochemical events seems to logically link turkey to an afternoon nap, solidifying the myth in the minds of many.

However, scientific evidence reveals a different picture. While turkey does contain tryptophan, its levels are not exceptionally high when compared to other common foods like chicken, cheese, or even nuts. The true culprits behind that overwhelming desire for a post-dinner snooze are far more likely to be the sheer volume of food consumed, particularly the abundance of carbohydrates and fats often found in holiday meals. A large intake of these nutrients requires significant digestive effort, diverting blood flow to the stomach and intestines and away from other areas, which can contribute to a feeling of lethargy.

The widespread belief in turkey's sleep-inducing powers persists largely because the timing of its consumption often coincides with large, indulgent meals. These feasts, typically rich in starches, sugars, and fats, naturally lead to a feeling of fullness and sluggishness regardless of the main protein. The association with turkey becomes a convenient, albeit inaccurate, explanation for a very real physiological response to overeating and the metabolic demands of digesting a substantial meal.