My favorite iNet Thanksgiving question/answer pair:
Thanksgiving Myth: Turkey Makes You Sleepy
The sleepy-turkey myth lingers around each year because it sounds so logical.
Alas, it is only marginally true. What's making you sleepy after Thanksgiving dinner is any combination of booze, bad conversation and a carbohydrate-heavy meal, but not the turkey itself.
Turkey does have tryptophan. But all meat has tryptophan at comparable levels. Cheddar cheese, gram for gram, has more.
In essence, big meals with any food containing tryptophan can cause sleepiness. The real culprits are all those carbohydrates from potatoes, stuffing, vegetables, bread and pie. The massive intake of carb-heavy calories stimulates the release of insulin, which in turn triggers the uptake of most amino acids from the blood into the muscles except for tryptophan.
With other amino acids swept out of the bloodstream, tryptophan—from turkey or ham or any meat or cheese, for that matter—can better make its way to the brain to produce serotonin.
Bonus Thanksgiving Funny via JibJab