Information
About Dietary Carbohydrate
What are Carbs?
Carbohydrates (the name derives from carbon
plus water) are one of three types of nutrients - the other two being
protein and fat.
Nearly all foods (except for oils/fats) contain a mixture of carbs, protein
and fat, but what makes carbs different is that they are easily converted
to energy by the body, so they supply most of our energy needs. This doesn't
mean that carbs are more nutritious than fats or protein. Both fat and
protein are absolutely vital for good health, and without a balanced diet
of carbs, fat and protein, the human body quickly becomes malnourished.
Recommended Daily Allowance for Carbs
According to the Dietary Guidelines for
Americans, published 2002, we should eat enough carbohydrates (mainly
the complex low glycemic-index type of carbs) to account for 45-65 percent
of our daily calories.
What are the Types of Carbohydrate?
Simple and Sugary Carbohydrates
Simple carbohydrates are sugars, like glucose, fructose and lactose. Common
sources include table sugar (sucrose), boiled sweets, syrups and honey.
Complex and Starchy Carbohydrates
Complex carbs are either starches, or indigestible dietary
fiber. Common sources of starches include, bread, pasta, rice, beans
and some vegetables. Common sources of dietary fiber are fruits, vegetables,
beans, and the indigestible parts of wholegrains like wheat bran and oatbran.
Carbohydrate Foods Classified by the Glycemic
Index
Recently, the Glycemic
Index (GI) has become the standard for classifying carbohydrates.
The glycemic index is a measure of how fast a particular carb-containing
food causes blood sugar to rise, compared with glucose. The higher a food
is listed on the glycemic index, the faster it causes blood-glucose levels
to rise. Foods are divided into high, medium or low glycemic index foods.
In very simple terms, high-fiber foods tend to be lowest on the GI scale,
while other complex carb foods tend to be medium GI, while simple carbs
tend to have the highest GI value. However, some starchy foods (even though
they are classified as complex carbs) can have a high glycemic value.
Carbohydrates Classified by Their Glycemic
Load
As stated above, the glycemic index compares
and classifies foods according the impact they have on blood-glucose.
However, it doesn't measure normal portion-sizes: instead, it measures
50 grams of carbs in each food. So if a particular food contains only
10 percent carbs, the glycemic index measures 500 grams of that food,
which can be quite an unrealistic measure. In comparison, a food's glycemic
load value is based on normal portion-sizes. For more information, see
Glycemic Load
Effects of Carbohydrates on Blood Sugar
Due to their differing chemical structures,
simple carbs and complex carbs affect the body in different ways.
Simple and Sugary Carbohydrates
Simple carbs are basically sugars (glucose) so they are very quickly assimilated
into the bloodstream, causing a rise in blood-glucose levels. Because
blood sugar-levels must be maintained within a certain healthy range,
the body responds by telling the pancreas to secrete insulin into the
digestive system, as insulin helps to "soak up" excess blood
sugar and disperse it to other parts of the body. Unfortunately, the pancreatic
gland typically "overreacts" to any sudden rise in blood sugar
and secretes too much insulin. As a result, within an hour or so, the
insulin has removed too much blood sugar, causing levels to drop which
in turn triggers hunger. This rapid rise and fall in blood sugar levels
caused by excess production of insulin, is not good for our health or
our eating habits.
Complex Carbohydrates
By comparison, complex carbs generally (but not always) need more time
to be broken down into glucose. So they don't raise blood sugar levels
as fast as simple carbs. This is why dietitians and nutritional experts
advise that we limit our intake of simple carbohydrates and eat complex
carbohydrates instead. That said, when choosing carbohydrate-rich foods,
be guided by the Glycemic Index. Not all complex carbs are equally beneficial
for good glycemic control.
Fiber
Dietary fiber is such
a complex type of carbohydrate that the human body cannot metabolize it
(break it down into glucose or other nutrients) at all. So it passes through
the body mostly undigested. However, fiber is very important for both
health and weight control because it helps the body to process waste efficiently
and helps us to feel fuller for longer. Fiber also helps protect us against
some serious diseases, including various cancers.
Nutrition Resources About Carbohydrate
Carbs:
RDA and Information
Best Carbs in Diet
Carbohydrates, Diet and Health
Vitamins in Carbs
Minerals/Trace Elements in Carbs
Phytochemicals in Carbs
No Carb Diet
Ketosis
Ketogenic Diet
Carbs, Fat and Diet
Carbs for Breakfast
Carbs, Diet Nutrition and
Calories
Low Carb Diets, Calories
and Weight Loss
Calories, Carbs and Diet
Low Carb Foods - Read Labels
Carb Intake in Diet
Dietary Fat, Cholesterol
and Strokes
Atkins Diet - Health Questions
Atkins Diet and Health
Atkins Diet and Weight Loss
Atkins Diet - Kidneys
and Osteoporosis
Low Carb Diets - Health
Concerns
High Carb Diets and Liver Problems
What is the Glycemic Index
How is Glycemic Index
Measured
GI of Bread, Potatoes,
Rice and Pasta
What Affects Glycemic
Index Values of Carbs
Carbs and the Glycemic Index
Glycemic Index and Weight
Loss
Low Glycemic Index Diets
and Weight Loss
Low Carb Diets and Nutrition
High Protein Diets
to Maintain Weight
Diet Fat and Heart Disease
Carbs, Diet and Cancer
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