Transcript Carbohydrates

Carbohydrates
What are carbohydrates?
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1 of the 6 essential nutrients and your body’s
main source of energy
Sugars, starches and fibers in your diet
How Much Do You Need?
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Follow the MyPyramid recommendations
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2 cups of fruit per day, 2 ½ cups of vegetables per
day, and 6 ounces of grains
Simple Carbohydrates
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Sugars
Natural sugars
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lactose in milk, fructose in fruit
Accompanied by vitamins and minerals
Refined sugars
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Table sugar. No nutritional benefit
Candy, soft drinks, cookies, cakes
Complex Carbohydrates
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Polysaccharides
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Starch and fiber (found in plants)
Excellent source of vitamins, minerals and fiber
Breads, cereal, rice, pasta, vegetables
Fiber
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Is the non-digestible portion of food that helps
maintain regularity and keeps the digestive
tract healthy. Some types of fiber may help
prevent cancer, lower blood cholesterol and
decrease risks of heart disease.
Good food sources are breads, fruits, and
vegetables (oatmeal, cabbage, carrots,
beets, cauliflower)
Carbohydrates
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Health benefits by choosing more complex
and fewer simple carbohydrates
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Top 5 carb sources for US Adults
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Bread, soft drinks, cookies and cakes, sugar/syrups,
potatoes
Are these good choices?
Objectives
1. List the functions of carbohydrates.
2. Explain how the body uses carbohydrates.
Four Key Functions of Carbohydrates
•Provide energy
•Spare proteins
•Assist in the breakdown of fats
•Provide bulk in the diet
Functions of Carbohydrates:
Provide Energy
•your body’s top priority is to provide enough energy for
all cellular activities needed to sustain life
•carbohydrates are the preferred source of energy
WHY?
Because your body can use them
efficiently as a fuel supply
If your diet does not provide enough carbohydrates, your
body will
draw mainly upon proteins for fuel needs
Functions of Carbohydrates:
Spare Proteins
Background Information:
•if needed, your body can use proteins as an energy
source
•your body is less efficient in using proteins
•if you eat too little carbohydrates, your body will use
proteins for its major functions
By eating adequate amounts of
carbohydrates, you spare the proteins—
this means you allow the proteins to be
used for their more vital roles
Functions of Carbohydrates:
Break Down Fats
If the diet is too low in carbohydrates, the body
cannot completely break down fats
Incompletely broken down fats form compounds
called ketone bodies
Ketone bodies collect in the blood stream and
become acidic—causing damage to cells and
organs (ketosis)
Functions of Carbohydrates:
Provide Bulk in the Diet
•fiber is the carbohydrate responsible
for this task
•fiber helps promote normal digestion
and elimination of body wastes
•fiber swells and makes you feel full
•fiber also slows the rate at which the
stomach empties
Functions of Carbohydrates:
Provide Bulk in the Diet
Benefits of Fiber in the Diet:
•Prevent appendicitis
•Decrease risk of heart and artery disease
•Lower risk of colon cancer
•Controls diabetes
soluble fiber: dissolves in water and develops a gel-like
consistency—it helps lower blood cholesterol levels
Example: oat bran, legumes
insoluble fiber: does not dissolve in water—it helps
reduce the risk of certain cancers
Example: wheat bran and whole grains
How Your Body Uses Carbohydrates
•all carbohydrates must in the form of
glucose for your cells to use them as
energy sources
•to get them in this form, your
digestive systems first breaks down
all poly-and disaccharides into
monosaccharides
How Your Body Uses Carbohydrates
The monosaccharides are small enough to move
across the intestinal wall into the blood
They travel via the blood to the liver
Any fructose and galactose in the blood is
converted to glucose in the liver
Functions of Carbohydrates
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Provide Energy
Spare proteins
Help in the breakdown of fats
Provide bulk in the diet
Provide Energy
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Carbohydrates provide 4 kilocalories per
gram
Body’s preferred source of energy
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So if I have a food with 10 grams of
carbohydrates, how many calories would that food
provide?
Spare Proteins
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Proteins build and maintain cell structure
If you do not eat enough carbohydrates, your
body will begin to use proteins for energy
If proteins are used as energy, they can’t be
used to build and maintain cell structure
Help in the Breakdown of Fats
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If you don’t consume enough carbohydrates,
your body cannot completely break down fats
Your body will begin to breakdown it’s own
stored fat for energy
This may lead to ketosis and this could cause
a person to slip into a coma and die
Complex Carbohydrates
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Starches and Fiber
Too Much Carbohydrate
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Dental carries/cavaties
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Sticky carbohydrate foods like raisins, cookies, crackers
and caramels tend to cling to teeth and cause tooth decay
Weight gain
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Sugars and starches you eat are converted to glucose in
the bloodstream and stored in the liver as glycogen. The
liver can only store a limited amount of glycogen. When
you consume more carbohydrate than the liver can store, it
is converted to fat. The body can store an unlimited amount
of fat.
Too Little Carbohydrate
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Ketosis
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Associated with low carbohydrate diets
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Glucose is the preferred source of energy. When that is
not available, the body begins to draw on fat stores for
energy
Symptoms include:
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tiredness, headache, feeling thirsty all the time, bad breath,
metallic taste in the mouth, weakness, dizziness, nausea or
stomach ache, sleep problems
Which would be a better source of energy
for a distance runner?
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How did you come to your conclusion?
OR
Video
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A short video summing up what we’ve
discussed
Answering these questions:
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List 2 foods that contain starches
What are healthy sources of sugars?
Sugars are broken into __________ to be used as
energy by the body.
Types of Carbohydrates
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Saccharides (sugar units)
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Monosaccharides-single sugar units
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Disaccharides (2 sugar units)
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Glucose (blood), fructose (fruits) and galactose (milk)
Sucrose (table sugar), maltose, lactose (milk)
Polysaccharides (many sugar units)
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Starch, fiber (found in plant foods)
Functions of Carbs
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Provide Energy
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Preferred source of energy; your body uses
effeciently
Spare Proteins
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Don’t eat enough carbs, have to breakdown
proteins for energy
Proteins are vital to build and maintain cell
structure
Functions of Carbs
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Break down fats
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Low carbs, can’t completely break down fats
Can cause ketosis ( damage organs and make
breath smell like nail polish remover)
Provide bulk in the diet
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Fiber helps maintain a healthy digestive system
Provide Bulk
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What is bulk?
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To increase in size; expand, swell
When you eat fiber, it swells helping you stay
full longer
Starches
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Starches are our body’s preferred source of
energy
Starches are an excellence source of
vitamins, minerals and fiber
Examples include rice
breads, cereals, pasta,
dry beans
Meeting Your Carbohydrate Needs:
Starches
•Starches are the preferred source of fuel for
your diet.
•Your body can burn them efficiently for energy
and they have greater satiety value than simple
sugars.
•Many starchy foods are also excellent sources
of vitamins, minerals and fiber.
Meeting Your Carbohydrate Needs:
Fiber
Determining fiber needs
•Take your age and add 5 to determine how many
grams of fiber you should include in your diet daily
Example: if you are 15 years old,
15+5= 20 grams of fiber per day
Use this formula to age 20, then aim for 25 to 35
grams of fiber per day
Meeting Your Carbohydrate Needs:
Fiber
How to increase your fiber intake
•Choose whole grain products
•Use fiber supplements
supplement: a concentrated source of a nutrient, usually
in a pill, liquid or powder form
Increase your intake of fiber slowly and
drink plenty of water.
Using Food Labels to Meet Your
Carbohydrate Needs
Examples of refined sugars
brown sugar
invert sugar
corn sweetener
sucrose
corn syrup
lactose
dextrose
maltose
fructose
honey
glucose
molasses
sugar
Health Questions Related to
Carbohydrates
Does sugar cause hyperactivity?
hyperactivity: a condition in which a person
seems to be in constant motion and is easily
distracted
•Researchers have conducted many studies but
have found NO proof that consuming sugars
causes behavior changes in most people.
•Sugar only gives children energy needed to fuel
activity.
Health Questions Related to
Carbohydrates
Is sugar addictive?
•Some people seem to crave sweets all the time—some believe this type
of craving qualifies as an addiction, or habitual need.
•Experiments have shown that if animals have a poorly balanced diet,
they will eat excessive amounts of sugar.
•Research has shown people are born with a preference for sweet-tasting
foods.
•Researchers think the need for sugar is more psychological than
physiological—in other words, people eat sweets because they enjoy
them, not because they are addicted to them.
Diabetes
diabetes mellitus: a lack of or an inability to use the hormone insulin
sugar and starch convert to glucose
which enters the bloodstream
insulin regulates the blood glucose level by
stimulating cells to pull glucose from the
bloodstream
when the body does not make enough insulin or fails
to use insulin correctly, glucose builds up in the
bloodstream
Diabetes
Two types of diabetes
Type I or insulin-dependent diabetes—the pancreas is not able to
make insulin
•Occurs most often in children and young adults
•must use insulin injections
Type II or non-insulin-dependent diabetes—body cells do not
respond well to the insulin the pancreas makes
•More common
•Occurs in adults over 40
•Can be controlled with diet
Diabetes
Symptoms of Diabetes
•Excessive hunger and thirst accompanied by weakness,
irritability and nausea
•Changes in eyesight
•Slow healing of cuts
•Drowsiness
•Numbness in legs, feet or fingers
Hypoglycemia
hypoglycemia: a low blood glucose level
an overproduction of insulin causes blood sugar to drop
sharply 2-4 hours after eating a meal
the CNS depends on a
constant supply of glucose
from the blood
when sugar is too low, physical symptoms appear—sweating,
shaking, headache, hunger and anxiety
Lactose Intolerance
lactose intolerance: an inability to digest lactose,
the main carbohydrate in milk
•This condition is caused by a lack of the digestive
enzyme lactase, which is needed to break down
lactose.
•People who are lactose intolerant may experience
gas, cramping, nausea and diarrhea when they
consume dairy products.
•Occurs more often among nonwhite populations
and tends to develop as people age.