Why Do We Feel Fatigued After the Thanksgiving Feast?
There’s an old wives’ tale roaming around that I always hear during Thanksgiving: eating turkey makes us feel sleepy because it contains Tryptophan. This is largely a false statement, and as Dr. Helmenstine points out, we would feel the lethargy after the Thanksgiving feast even if we took turkey out of the meal completely.
L-Tryptophan is an amino acid, which is indeed found in turkey. This amino acid is metabolized in our body into serotonin and melatonin, which make us relaxed and wanting a nap. However, this isn’t the cause of the post-dinner fatigue for 2 reasons. First, Tryptophan would have to be consumed on an empty stomach in order for its effects to be noticed. Second, there are many other foods we eat on a regular basis that contain more Tryptophan than turkey (i.e. chicken, pork, cheese, etc.), and we don’t complain of feeling sleepy after eating those! Furthermore, Coco Balyntine states that Tryptophan is actually the scarcest of the amino acids present in turkey and other proteins. She also mentions that Tryptophan would need to be consumed without any other amino acids to increase serotonin in the brain, and no food source fits those criteria.
There are a few other more likely reasons for the Thanksgiving lethargy. For example, Dr. Helmenstine suggests that the meal is usually contains high concentrations of fatty foods. A lot of energy is required to digest fats. To make matters worse, most people probably overeat during the feast; I know I do! The high amount of energy required to digest the fat can be a contributing factor to sleepiness after the meal. Other possible contributing factors could be the consumption of alcoholic beverages or even just the fact that the meal was the first time on Thanksgiving Day that you got to sit. Balyntine proposes that dessert is the culprit for our sleepiness as it is high in carbohydrates.
Thus we can no longer blame turkey itself for our post Thanksgiving food coma. Since the bird has been freed from years of misplaced blame, we can all go enjoy our own Thanksgiving meals with peace of mind!
Ballyntine, Coco. “Does Turkey Make You Sleepy?” Scientific American Global RSS., 21 Nov. 2007.
Helmenstine, Anne Marie, Ph.D. “Why Does a Big Turkey Dinner Make You So Sleepy?” About.com Education.