Carbohydrates in Food:
What are carbohydrates?
The subject of carbohydrates in
food, a rather simple subject, has become wild and confusing
in recent years due to the avalanche of information that
has appeared about different types of diets - high carb?
Low carb? Are they good for us or bad?
This article will answer the question,
"What are carbohydrates?" so you can sort the true
information about carbs from the fiction.
Want to have some fun? Type "carbohydrate myths" into
your search engine. Whoa... you'll find that there's
a lot of information going around that really
isn't true at all about carbohydrates in food! For
example, it is not true that all carbohydrate
is "bad" or that sugar is a separate food group -
sugar is carbohydrate. So are so-called "starchy" vegetables
- all carbohydrate.
What ARE carbohydrates?
Carbohydrate is one of the 4 primary
macronutrients that the body needs in order to run well.
("Macro-" meaning large, macronutrients are
needed in large quantities compared to the micronutrients
of vitamins and minerals.)
The other 3 macronutrients are protein,
fats and water. The term "carbohydrate" comes
from "carbon + hydrogen" which are the elements
it's made of, plus oxygen.
The function of carbohydrates in food
is to provide quick fuel for energy. The other source
of energy, which breaks down more slowly, comes from the
different types of fat.
Carbohydrates in food come from plants.
Breads, cereals, fruits, vegetables and legumes* are the
main
sources of the nutrient carbohydrate. Additionally, a large
percentage of the protein you consume is converted to carbohydrate
and stored in the liver.
* A legume is a kind of plant that has
pods, such as peas and beans.
If protein is the building and repairing
material for the body, like bricks and cement for a building,
then carbohydrates are like the construction workers, providing
the energy that gets the materials moved around and put
in the right place.
Types of carbohydrate
When one asks "What are carbohydrates,"
the answer includes learning the three forms
of carbohydrates
in food:
- sugars
- starches and
- fiber
Sugars are the type
of carbohydrate found in fruits and vegetables. The term "sugars"
means more than just refined table sugar that you sprinkle
on your cereal or put in your coffee.
These are called "simple"
sugars or simple carbohydrates because they are made of
just a few sugar molecules and digest quickly.
Refined carbohydrates
When the carbohydrates in food are refined,
most of the parts that are rich in nutrients are taken out.
That's why too many of those gooey, finger-lickin'
sugary things aren't so good for you - they
don't have anything in them that nourishes your body.
Refined carbohydrates, such as processed
white flour, are in the simple sugar category. Too many
refined carbohydrates are the "bad carbs" and
unfortunately, give the rest of the "good carbs"
a bad name.
What are complex carbohydrates?
Starches are the kind
of carbohydrate found in foods such as grains, cereals,
whole grain breads, beans, potatoes, legumes and pastas.
They are called "complex" carbohydrates because
they are composed of many glucose molecules and take longer
to break down during digestion and be absorbed by the body.
What's dietary fiber?
Dietary fiber is also
a complex carbohydrate that comes from the thick cell wall
of plants. The body cannot fully digest fiber, but fiber
contains minerals and other nutrients that are absorbed
and contribute to good health.
There are two kinds of fiber,
water soluble and water insoluble fiber. "Soluble"
means able to be dissolved.
Soluble fiber can absorb
water and slow down digestion of the carbohydrates in food,
allowing more time for nutrients to be absorbed. Soluble
fiber helps to keep blood glucose (also called blood sugar)
more level (instead of swinging way up or down) because
the fiber causes the carbohydrates in food to be absorbed
more slowly.
Oats, beans, dried peas, and legumes are
good sources of soluble fiber.
Insoluble fiber can't
absorb water. It's what we generally think of as "roughage" -
although it's not really rough at all! It is important
to digestion and elimination. Wheat bran, whole
grain products, and vegetables are major sources of insoluble
fiber.
Fruits, vegetables, and barley contain
both soluble and insoluble fiber.
What is glucose? Glucose demystified
The carbohydrates in food break
down into a simple sugar molecule called glucose
during digestion, which is then absorbed into the bloodstream.
Glucose is the main source of energy for the body.
Glucose enters the bloodstream and travels
to all the cells of the body, where the hormone insulin
"opens the cell doors" and allows the glucose
to enter the cell. The glucose then combines with oxygen
in the cell to produce energy.
Carbohydrate can be used immediately
or stored in the liver and tissues for future energy needs.
To learn what foods contain
carbohydrate, look at the nutrition
fact label on packaged
food for a start.
I hope this article has been useful to
you,
Cheers!
What
exactly is the
glycemic index
(The "GI"??)
The word "glycemic"
means "causing glucose (sugar) in the blood."
Carbohydrates are "glycemic"
because they break down into glucose (a form of sugar
used for energy in the body.)
The word "index"
in this sense means a numerical scale used to compare
things.
Foods with carbohydrates
range on the glycemic index from 1 - 100 depending
how fast and how much they raise blood sugar levels.
For example, white bread
breaks down very quickly, causing blood sugar to rise
rapidly. So it has a high glycemic index value of
70.
Spaghetti is digested more
slowly, causing a lower and more gradual change in
blood sugar. So it has a low glycemic index value
of 38.
Just think "LOW = SLOW"
to remember that a low GI value means that the carbohydrate
digests and absorbs slowly.
The glycemic index expands
on the fact that simple carbohydrates digest rapidly,
increasing blood glucose faster and for a shorter
time, while complex carbohydrates digest more slowly,
causing a slower and longer rise in blood glucose.
The glycemic index measures
the "power" or quality of carbohydrate only.
It doesn't measure the effects on blood sugar
level of the quantity of the carbohydrate that
is eaten. (A ton of spaghetti is a ton of spaghetti!)
Although there are a number
of good web sites with information about the glycemic
index, I recommend the official GI web site http://www.glycemicindex.com/
to start with if you want more information. This
site includes a large database of different carbohydrate
foods and their GI value.
I also recommend the
book "The New Glucose Revolution" which I read several
years ago. It is written by the doctors and nutritionists
who have developed the GI technology at the University
of Sydney.
I found it easy reading,
written for us "regular folks." This and a number
of other books on the glycemic index are described
on the site along with lots of other great information,
including a database of foods and their GI value. |
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