CARBOHYDRATES

CARBOHYDRATES
The carbohydrates are a vast and diverse group of nutrients
found in most foods. This group includes simple sugars
(like the sugar you add to your morning coffee) and complex
forms such as starches (contained in pasta, bread, cereal,
and in some fruits and vegetables), which are broken down
during digestion to produce simple sugars. The main
function of the simple sugars and starches in the foods we
eat is to deliver calories for energy. The simple sugar glucose
is required to satisfy the energy needs of the brain, whereas
our muscles use glucose for short-term bouts of activity.

The liver and muscles also convert small amounts of the
sugar and starch that we eat into a storage form called
glycogen. After a long workout, muscle glycogen stores
must be replenished. Both simple sugars and starches
provide about 4 calories per gram (a gram is about the
weight of a paper clip).

Because carbohydrates serve primarily as sources of calories (and we can get calories
from other macronutrients), no specific requirement has
been set for them (see Chapter 1, The Dietary Reference
Intakes [DRIs], page 5). But health experts agree that we
should obtain most of our calories (about 60 percent) from
carbohydrates. Our individual requirements depend on
age, sex, size, and activity level.

In contrast to the other carbohydrates, fiber (a substance
contained in bran, fruits, vegetables, and legumes) is a type
of complex carbohydrate that cannot be readily digested by
our bodies. Even though it isn’t digested, fiber is essential
to our health. Nutrition professionals recommend 25 to 30
grams of fiber daily.