The reason so many people get sleepy after Thanksgiving dinner
— like many other meals and snacks — is not caused by eating turkey,
but rather by eating all the trimmings made from refined carbohy-
drate and sugar. In the case of a typical holiday meal, it’s the bread,
potatoes (including sweetened sweet potatoes), gravy (made with
flour), cranberries (sweetened with sugar), and of course those extra
servings of pie (there’s always more than one type to taste). Throw in
some alcohol and it’s no wonder you’re craving more than just one
pot of coffee.
While turkey does have a high amount of tryptophan, it has
many other amino acids that prevent tryptophan levels from elevat-
ing in the blood (thereby not affecting the brain). The foods that
reduce brain function the most are the carbohydrates which cause a
rise in a brain neurotransmitter, serotonin — this has a calming, relax-
ing, sedating effect on the brain, with the more carbohydrates you eat,
the more sedating its action.
Sleepiness after any meal may be indicative of carbohydrate intol-
erance. So if you often feel this way, it’s time to evaluate, or re-evalu-
ate your eating habits as I discussed in the chapters on carbohydrates.
High-carbohydrate foods cause the brain to produce more serotonin.
The individual who is easily agitated or mentally overactive may ben-
efit from a meal with natural carbohydrates that are not high-
glycemic. Too many carbohydrates, however, can produce too much
serotonin in many people, causing oversedation or even depression.
If you’re a student, executive, or just want to use your brain better,
you might find that eating sufficient carbohydrate to adversely affect
brain chemistry is counterproductive.
While sweets are traditionally thought of as providing energy,
they are in actuality mentally sedating. Sometimes sweets may give
the feeling of a pick-up, but that is very short-lived, until insulin low-
ers the blood sugar, resulting in more fatigue.
If you need a mental pick-up, try eating some protein. A protein-
based meal with little or no carbohydrates causes your body to pro-
duce less insulin, and provides a higher amount of tyrosine and
increased norepinephrine levels. This neurotransmitter has a stimu-
lating effect on the brain. The person who needs a mental pick-up or
who gets sleepy after a meal could benefit from eating a high-protein
meal with little or no carbohydrate.
246 • IN FITNESS AND IN HEALTH