Macronutrients
Carbohydrate
Function
Carbohydrates and Nutrition
There have been major advances in
the understanding of how
carbohydrates influence human
nutrition and health in recent years.
Progress in scientific research has
highlighted the diverse functions of
carbohydrates in the body and their
importance in the promotion of good
health.
Energy & Taste

Energy: cell respiration

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Transformation of glucose to ATP fuels
the body’s functions
The brain, nerve cells, and developing
red bloods cells use glucose almost
exclusively for energy
Dietary carbohydrates provide the
carbohydrates needed for this process
Taste/Flavor / Sweetness
(sucrose, fructose)
Intestinal Health &
Cellular Recognition


Proper intestinal health (fiber)
Structural components of
glycoproteins and glycolipids;
these are used for cellular
identification – how your body
recognizes itself (example:
blood type)
“Protein Sparing”

Protein sparing (gluconeogenesis)
 The body cannot convert fats into
glucose [for cell respiration] to a
significant degree (large amounts).
 So without glucose, the body may be
forced to break down its protein
tissues in order to convert to glucose
for energy, which can lead to muscle
loss.
Avoiding Ketoacidosis

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Fat metabolism  prevents incomplete
breakdown of fats; prevents ketone
production
When the body uses fat for energy, fat fragments
combine to form ketone bodies.
Some body cells can use ketone bodies for
energy, but if fat is broken down too rapidly,
ketone bodies begin to accumulate in the blood.
This can cause a serious condition called ketosis
that can lead to coma and death.
Amount of Dietary Carbohydrates You
Need…
 The
body needs at
least 50 to 100 grams
of carbohydrates a day
to spare body proteins
and prevent ketosis
Simple Sugars
Some
examples of simple
sugars are glucose, fructose,
sucrose, and lactose
Food sources for simple
sugars??
Complex Carbohydrates
Some
examples of complex
carbohydrates are starch,
glycogen, and fiber
STARCH
 Starch
is the most consumed
polysaccharide in the human diet
 Found in rice, wheat, corn, and
potatoes, peas, bananas, various
forms of bread and noodles (including
pasta).
 Cornstarch is used in cooking for
thickening foods such as sauces
 Plants store glucose as amylose and
amylopectin (types of starches)
FIBER
Dietary
fibers are the
indigestible portion of plant
foods
Non-starch polysaccharides
such as cellulose
Fiber is NOT used for energy
Insoluble Fiber



Functions of Insoluble Fiber
 Move bulk through the intestines
 Control and balance the pH (acidity) in the
intestines
Benefits of Insoluble Fiber
 Promote regular bowel movements and
prevent constipation
 Remove toxic waste through colon
 Help prevent colon cancer
Food Sources of Insoluble Fiber


Vegetables such as green beans and dark green leafy
vegetables; Fruit skins and root vegetable skins
Whole grain products; Seeds & Nuts
Soluble Fiber



Functions of Soluble Fiber
 Prolong stomach emptying time so that sugar is
released and absorbed more slowly (makes you feel
full longer)
Benefits of Soluble Fiber
 Lower total cholesterol and LDL cholesterol (the ‘bad
cholesterol’) therefore reducing the risk of heart
disease
 Lowers blood sugar
Food Sources of Soluble Fiber
 Oat/Oat bran
 Soybeans and peas
 Nuts & Barley
 Some fruits particularly prunes, plums, berries
 Vegetables such as carrots, green beans, celery
GLYCOGEN
 Surplus
glucose is linked together and
stored as glycogen
 Functions as the body’s main energy
reserve
If there is no glucose, glycogen is
available to be broken down into
glucose and used
Glycogen Continued…
The
conversion of glucose
to glycogen and glycogen
to glucose are the usual
mechanism for
maintenance of normal
levels of blood sugar