Ask Food: Why we get sleepy after Thanksgiving dinner

Q: Why do I get sleepy after Thanksgiving dinner?

A: You always hear about tryptophan around Thanksgiving time. Folks warn that getting too much turkey (one of the most well-known sources) puts you in a "food coma." Is it really to blame for that post-dinner snooze?

This specific amino acid is considered "essential," which means your body can't make it on its own -- you can only get it from food. All types of protein-rich foods are made of a combination of amino acids. Tryptophan is important because it helps the body produce two must-haves: the B-vitamin niacin and the chemical serotonin. As with many other nutrients, supplements exist, but research has found these can cause some dangerous side effects. So stick to the safest version -- tryptophan found naturally in your food!

The food myth has to do with tryptophan's help in forming serotonin, which is involved in sleep regulation, appetite control and mood. The reality is that you would have to eat tryptophan alone and on an empty stomach (not likely on Thanksgiving) in order for it to make you feel sleepy. Because foods that contain tryptophan also contain other types of amino acids, that holiday turkey isn't what's making you tired. In fact, turkey's tryptophan content isn't even as high as it is in chicken and cheese.

The reality: Overeating, drinking alcohol and consuming a high-fat meal, which takes more time and energy to digest, are more likely the causes for that Thanksgiving afternoon nap.

Other than turkey, here are some major sources of tryptophan:

Cheese

Chicken

Eggs

Fish

Mushrooms

Nuts

Peanut butter

Pork

Pumpkin (and pumpkin seeds)

Spinach

Tofu

Turkey

Turnips

See a lot of familiar Thanksgiving dishes lurking in that list?