Several years ago I was a guest at a dinner at which a colleague was giving an important after-dinner talk. The dinner itself was elaborate. A long cocktail hour was followed by a four-course dinner with matching wines. Crab cakes with a creamy sauce were followed by cream-based lobster bisque. The entrée was filet mignon with cheese-sauced potatoes and asparagus in Hollandaise sauce. The dense, flourless, rich chocolate cake was accompanied by a sweet dessert wine. As each meal contained enough calories for a family of four, I nibbled and drank water as my fellow dinners cleaned their plates and emptied their wine glasses.
I knew what would happen when the speech began. The lengthy introduction gave just about enough time for all the food to begin its march through the digestive system accompanied by an increased blood flow to the gut. Then, as the speaker rose to start his talk, heads all over the dining room flopped to their respective tablecloths and a gentle snoring could be heard around the room. In a few minutes the speaker and I were the only ones awake. It was a good speech, and I suspect my vigorous clapping woke the diners up in time to show their appreciation.
Moral of this true tale: If you want to keep your brain awake, be careful what you put into your stomach.
Eating a large amount of food in a relatively short period of time will divert blood flowing to the brain to the intestinal tract. A comfortable drowsiness will follow. This may be a happy consequence for someone desiring to sleep through a boring speech, concert or dance recital. However, since we are not toddlers who expect to be put to bed for a nap after a meal, the sleepy brain may make it hard for us to work, converse intelligently or even drive with sufficient alertness.
What is eaten may also have a direct effect on whether our brain is awake and alert or muddled and drowsy. And the effect is felt as soon as the food or drink is consumed and digested.
In order of decreasing effectiveness, here is a short list of how to keep yourself mentally awake.
1. Caffeine. Caffeinated beverages like coffee, tea, and colas affect certain brain chemicals almost immediately and cause the brain seemingly to work faster, more effectively and even with greater motivation. How much caffeine is needed to do this depends on the individual. People who consume very little caffeine can feel stimulated with a Diet Coke or cup of tea. Those who consume large quantities of caffeine may feel the effect only in the morning after their bodies have gotten rid of the caffeine from the day before. Caffeine is metabolized and leaves the blood stream after three or four hours. Often people who consume caffeine early in the morning will feel themselves needing a mental pick-up mid-afternoon because their caffeine levels have dropped by then. The English habit of drinking very strong tea late in the afternoon is an example of an entire nation embracing the need for a caffeinated beverage late in the day. Caffeine may or may not affect the ability to fall asleep, especially if consumed late in the afternoon or evening. Most people know whether it does or not after just one sleepless night.
2. Protein. Two chemicals in the brain, dopamine and norepinephrine, are made from tyrosine, an amino acid in protein. These chemicals or neurotransmitters are involved in mental alertness and reaction time. Eating protein for breakfast and again at lunch is protection against the brain going into a sleep mode at work. And obviously if work, classes or other activities that require an alert brain take place at night, protein should be eaten at dinner as well. Not much is needed; two or three ounces of a protein-containing food, like cottage cheese for breakfast, and three to five ounces of protein, such as chicken at lunch, is sufficient. Most of us do not work our brains into a fatigued, numb state so that we are unaware of our need for protein to get it working again. But someone taking a bar exam, or giving or answering questions at a ten-hour deposition, or trying to learn a new language in a four-hour language immersion class will know how it feels to have a brain in the need of protein.
