Tuesday, April 15, 2003

Why Do You Get Tired After Thanksgiving Dinner?

Ever feel really sleepy after Thanksgiving dinner? Ever watch your grandfather fall fast asleep after eating his Thanksgiving meal? You are not alone. Many people hit the hay after enjoying their Thanksgiving feast featuring everyone's favorite bird - the turkey. Some think that the turkey makes them tired. Is this true?

People think turkey puts them to sleep because it is made up of L-tryptophan. But what is L-tryptophan? L-tryptophan is an amino acid. An amino acid helps to build proteins. Proteins are very important to your body. Along with making up your muscles so you can move, proteins also control the billions of chemical reactions that happen in your cells every day. If these reactions did not take place, you would not be able to make stomach acid to digest your food, produce sweat to cool yourself off in the summer, get oxygen and nutrients from your blood to your cells, fight off infections or do pretty much everything your body needs to do to stay alive.

Proteins are made up of various amino acids, not just L-tryptophan. Humans need to eat nine "essential" amino acids to survive. L-tryptophan is one of these nine. It is a normal and important part of everyone's diet. L-tryptophan is also natural sedative or, in other words, a compound that relaxes people and makes them sleepy. L-tryptophan also helps to make serotonin--a normal chemical in the brain that is also a sedative. Some people actually take L-tryptophan to help them fall asleep. But, in large amounts, it is not healthy and could cause serious problems such as death. As a result, the Food and Drug Administration, the government agency that decides which foods and drugs can be legally sold in the United States, banned it from being sold in this country.

Even though L-tryptophan can help you fall asleep, it is unlikely that the amount in your Thanksgiving turkey is putting you to sleep. This is because L-tryptophan only affects the brain if your stomach is empty and there are no proteins present. Do you plan on eating only turkey for Thanksgiving? What about those delicious food items on your plate such as candy yams and cranberry sauce? And, who can forget about that pumpkin pie? Also, turkey is made up of many proteins, so L-tryptophan would not be alone in your stomach even if you did pass up all the other delicious dishes.

As you can see, if you are tired after turkey, it is probably not the L-tryptophan in your turkey that is making you fall asleep. You are probably just tired from helping your parents cook that great, big meal or from working up an appetite while playing football outside with all your cousins or from simply overeating. Overeating---not just turkey, but mashed potatoes, cranberries, yams, peas, carrots, bread, pies, and whipped cream---demands a lot of blood to be pulled towards your digestive system to help break down all that food. This blood is pulled away from your brain. Your brain constantly needs blood for you to think and be alert. Losing even small amounts can cause you to feel tired. So, if you want to stay awake for desert or to watch the end of The Sound of Music or to see your neighbors start to put up their Christmas decorations, you should probably take your time and enjoy your meal. Don't fill up! And, after that delicious dinner, take a walk or help wash the dishes.

Little Lion Experiment:

Corn was a stable food item for the Indians because it was easy to grow and very nutritious. Try to grow your own!


  • Kernels of popcorn
  • Ziploc bag
  • Dirt
  • Water


Place a couple handfuls of dirt into your Ziploc bag; add a little water and a few kernels of popcorn. Then, seal the bag and place it in a sunny window. Observe your corn grow. In about a week, your corn should be sprouting

For the advanced scientist, you can make a couple bags of corn and test the effects of different amounts of sunlight, water and air. Be sure to record how much or how little you provided your kernels.