| MadSci Network: Biochemistry |
Aloha,
Let me begin with a bit of basic nutrition. 'Sugar' is a term for
simple carbohydrate; the most common type of sugar in our food supply is
probably sucrose (cane or beet sugar)...and it is 'pure' carbohydrate,
since it has been extracted and purified from one of those two plants.
All carbohydrates that can be absorbed by the human digestive tract
(sugars and starches) are handled the same way, once in the body. The
simple sugars that result from starch digestion are handled just the same
as the simple sugars directly absorbed, as is.
The main difference between how the body absorbs sugars from starches
or sugars, as they occur in nature or as they are added to processed
foods, is in the speed at which they are absorbed through the small
intestine into the blood stream. The simple sugars (glucose, fructose,
galactose)...sucrose is simply a chemical combination of glucose and
fructose)...are absorbed more quickly than those from starch, since the
starch molecules must first be broken down in the digestive tract into the
simple sugars, before they can be absorbed.
Now, to your question...'sugar,' especially when eaten as part of a
food, even a processed food, like a candy bar, would have little effect on
your ability to function (either physically or mentally), because any
effect would be blunted by the other nutrients (especially fat and
protein) which would be part of the food. Eating straight sugar might
have a small effect on your blood sugar (glucose) concentration, but your
body, when everything is working correctly, has very effective feedback
biochemical mechanisms (controlled mainly by the hormones insulin and
glucagon) to restore your blood glucose to a safe/normal range. The
tissues in your body rely on a certain range of glucose in the blood
stream to function properly, so the body will protect the blood glucose
level...this is what goes wrong when a person has diabetes...the control
mechanisms just don't work right...and the blood glucose gets way too
high, for too long...and permanent damage can occur.
I've actually done research in this field...looking at the effect of
high doses of sugar (sucrose) on behavior in juvenile delinquent males.
The interesting thing that we found was that in a subset of these
guys...the ones who had major problems with attention...sugar seemed to
calm them down and allowed them to complete some of the behavioral tasks
better...exactly what the biochemistry would predict...probably something
related to increasing serotonin levels in the brain (which we did not
measure directly).
If you were severly deficient in energy, then maybe a dose of sugar
would help you 'recup'...but, so would eating food...either containing
sugar or not. So, I guess my answer is that long-term, sugar would have
little effect on either academics or physical skills. Eating FOOD,
however, has been shown to have a large effect on learning...skipping
breakfast is not a good thing...this has been shown in a number of
studies. Likewise, semi-starving (like on a reducing diet or during
eating disorders) effects the brain because of lack of adequate calories,
and learning and physical functioning can be severly affected. Kind of
like trying to start a car with little/no gas in the tank (after an
overnight 'fast').
I hope this helps answer your questions.
Try the links in the MadSci Library for more information on Biochemistry.