Section 8.1 Carbohydrates, Fats, and Proteins
Carbohydrates, Fats, and Proteins
Objectives
Name the three classes of nutrients that supply
your body with energy.
Explain how the body obtains energy from
foods.
Describe the roles that carbohydrates, fats,
and proteins play in your body.
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Section 8.1 Carbohydrates, Fats, and Proteins
Quick Quiz Which of these statements are always true?
Which are sometimes true? Which are always false?
Foods that are high in calories are unhealthy.
You should avoid foods with sugars in them.
You should avoid fats in your diet.
Vegetarian diets are low in protein.
Snacking is bad for you.
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Section 8.1 Carbohydrates, Fats, and Proteins
Nutrition
The sum of the processes by which humans, animals,
and plants consume and use food is nutrition.
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Section 8.1 Carbohydrates, Fats, and Proteins
Foods Supply Nutrients
• Food supplies your body with nutrients, substances
in food that helps with body processes (regulate
bodily functions, promote growth, repair body
tissues, and obtain energy).
• There are six classes of nutrients: carbohydrates,
fats, proteins, vitamins, minerals, and water.
• Carbohydrates, fats, and proteins can all be used by
the body as sources of energy.
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Section 8.1 Carbohydrates, Fats, and Proteins
Foods Supply Energy
• The foods you eat are your body’s energy source.
• You need energy to maintain your body temperature,
keep your heart beating, and enable you to
understand what you read.
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Section 8.1 Carbohydrates, Fats, and Proteins
Fuel for Your Body
• When your body uses the nutrients in foods, a series
of chemical reactions occurs inside your cells. As a
result, energy is released.
• Metabolism is the chemical process by which your
body breaks down food to release as energy.
• Metabolism also involves the use of this energy for
growth and repair of body tissue.
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Section 8.1 Carbohydrates, Fats, and Proteins
What are Calories?
• The amount of energy released when nutrients are
broken down is measured in units called calories.
• The more calories a food has, the more energy it
contains.
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Section 8.1 Carbohydrates, Fats, and Proteins
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Section 8.1 Carbohydrates, Fats, and Proteins
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Section 8.1 Carbohydrates, Fats, and Proteins
Carbohydrates
• Carbohydrates are nutrients made of carbon,
hydrogen, and oxygen.
• Carbohydrates supply energy for your body’s
functions.
• A nutrient that is the main source of energy for the
body is a carbohydrate.
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Section 8.1 Carbohydrates, Fats, and Proteins
Simple Carbohydrates
Simple carbohydrates are sugars that enter the
bloodstream rapidly and provide quick energy.
• Simple carbs provide calories but few vitamins
and minerals.
Complex Carbohydrates
Complex carbohydrates are made up of sugars that
are linked together chemically to form long chains.
•Starch – a food substance that is made and stored in
most plants
• Provide long-lasting energy
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Section 8.1 Carbohydrates, Fats, and Proteins
Carbohydrates can be…
Simple Carbs
Complex Carbs
- Fruits
- Honey
- Milk
- Sugars added to cookies,
candies, soft drinks
-Grains (bread & pasta)
-Vegetables (potatoes &
beans)
-Rice
-Cereals
-Wheat
-Tortillas
-Whole-wheat rolls
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Section 8.1 Carbohydrates, Fats, and Proteins
Fiber
• Fiber is a type of complex carbohydrate that is found
in plants.
• A high-fiber diet
• helps prevent constipation
• may reduce the risk of colon cancer
• may help prevent heart disease
• The part of grains and plant foods that cannot be
digested is called fiber.
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Section 8.1 Carbohydrates, Fats, and Proteins
Insoluble vs Soluble Fiber
Insoluble
Soluble
• Binds with water to help
produce bowel
movements (prevent
constipation).
• Associated with reduced
risk of colon cancer.
• Good sources: wheat
products, leafy
vegetables, and fruits.
• Eating foods with soluble
fiber reduces your blood
cholesterol level and your
risk of developing heart
disease.
• Good sources: wheat,
bran, barley, rye, oats,
whole grain pasta,breads,
cereals…
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Section 8.1 Carbohydrates, Fats, and Proteins
Fiber
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Section 8.1 Carbohydrates, Fats, and Proteins
Your Body’s Energy Reserves
• At a meal, you usually eat more carbohydrates than
your body can immediately use.
• The extra glucose is converted into a type of starch
called glycogen.
• Glycogen is stored in the muscles and when you
need energy, it is converted to glucose.
• If you eat so many carbohydrates that the body’s
glycogen stores are full, then the excess
carbohydrates are stored as fat instead.
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Section 8.1 Carbohydrates, Fats, and Proteins
Daily Carbohydrate Intake
• Nutritionists recommend that 45-65% of a person’s
daily calorie intake come from carbohydrates.
• It is better to eat foods rich in complex carbohydrates
rather than simple carbohydrates.
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Section 8.1 Carbohydrates, Fats, and Proteins
Fats
• Fats are made of carbon, hydrogen, and oxygen.
• Fats supply your body with energy, form your cells,
maintain body temperature, and protect your nerves.
• A nutrient that provides energy and helps the body
store and use vitamins is a fat.
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Section 8.1 Carbohydrates, Fats, and Proteins
Unsaturated Fats
• Unsaturated Fats have at least one unsaturated
bond in a place where hydrogen can be added to the
molecule.
• Unsaturated fats are usually liquid at room
temperature.
• Unsaturated fats are classified as either
monounsaturated fats or polyunsaturated fats.
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Section 8.1 Carbohydrates, Fats, and Proteins
Saturated Fats
• Fats that have all the hydrogen the carbon atoms
can hold are called saturated fats.
• Saturated fats are usually solid at room temperature.
• Too much saturated fat in your diet can lead to heart
disease.
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Section 8.1 Carbohydrates, Fats, and Proteins
Daily Fat Intake
Nutritionists recommend that 20-35% of your calories
come from fat, primarily unsaturated fat.
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Section 8.1 Carbohydrates, Fats, and Proteins
Cholesterol
• Cholesterol is a waxy, fatlike substance that is found
only in animal products.
• Your body needs a certain amount of cholesterol to
make cell membranes and nerve tissue, certain
hormones, and substances that aid in the digestion
of fat.
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Section 8.1 Carbohydrates, Fats, and Proteins
Trans Fats
• Trans fats are made when manufacturers add
hydrogen to the fat molecules in vegetable oils.
• Trans fats are found in margarine, chips, and
commercially baked goods.
• Trans fat seems to have many of the negatives of
saturated fat.
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Section 8.1 Carbohydrates, Fats, and Proteins
Proteins
• Nutrients that contain nitrogen as well as carbon,
hydrogen, and oxygen are called proteins.
• Proteins can serve as a source of energy.
• A nutrient that is needed for growth, and to build and
repair body tissues is a protein.
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Section 8.1 Carbohydrates, Fats, and Proteins
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Section 8.1 Carbohydrates, Fats, and Proteins
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Section 8.1 Carbohydrates, Fats, and Proteins
Amino Acids
• Proteins are long chains of smaller “links” that are
bound together chemically.
• These smaller substances are known as amino
acids.
• The building blocks that make up proteins are amino
acids.
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Section 8.1 Carbohydrates, Fats, and Proteins
Essential Amino Acids
The nine amino acids that the body cannot
manufacture are called essential amino acids.
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Section 8.1 Carbohydrates, Fats, and Proteins
Complete and Incomplete Proteins
• Protein from animal sources is complete protein.
• It contains all nine essential amino acids.
• Most protein from plant sources is incomplete
protein.
• It lacks one or more of the essential amino acids.
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Section 8.1 Carbohydrates, Fats, and Proteins
Daily Protein Intake
Nutritionists recommend that 10-35% percent of your
calories come from proteins.
Proteins for Vegetarians
People who don’t eat meat can combine two or more
plant protein sources that, taken together, provide all
the essential amino acids.
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Section 8.1 Carbohydrates, Fats, and Proteins
Vocabulary
nutrient
A substance in foods that the body needs to
regulate bodily functions, promote growth, repair
body tissues, and obtain energy.
metabolism
The chemical process by which the body breaks
down food to release energy.
calorie
Unit for the amount of energy released when
nutrients are broken down.
carbohydrate
A nutrient made of carbon, hydrogen, and
oxygen and that supplies energy.
fiber
A way of dealing with an uncomfortable or
unbearable feeling or situation.
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Section 8.1 Carbohydrates, Fats, and Proteins
Vocabulary
fat
unsaturated fat
saturated fat
cholesterol
A nutrient made of carbon, hydrogen, and
oxygen; supplies energy, forms cells, maintains
body temperature, and protects nerves.
A fat with at least one unsaturated bond in a
place where hydrogen can be added to the
molecule.
A fat that has all the hydrogen the carbon atoms
can hold. A fat that has all the hydrogen the
carbon atoms can hold.
A waxy, fatlike substance that is found only in
animal products.
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Section 8.1 Carbohydrates, Fats, and Proteins
Vocabulary
trans fat
The type of fat produced when manufacturers
add hydrogen to the fat molecules in vegetable
oils.
protein
A nutrient that contains nitrogen as well as
carbon, hydrogen, and oxygen; needed for the
growth and repair of body tissues.
amino acid
Small units that are bound together
chemically to form proteins.
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Section 8.1 Carbohydrates, Fats, and Proteins
Questions
1)
2)
3)
4)
5)
6)
7)
Which 3 classes of nutrients supply the body with energy?
Define the term metabolism. How is metabolism related to the
nutrients in food?
What roles do the following nutrients play in the body? A.
carbohydrates B. fats C. proteins
What is cholesterol? How does diet affect cholesterol levels in the
blood?
Name a circumstance during which you might use your body’s
stores of glycogen.
How do saturated fats differ from unsaturated fats? Name 2
sources of each type of fat.
Suppose that you ate 2,500 calories/day. Of those calories, 1,200
calories were from carbs, 875 from fats, and the rest from protein.
What % of your total day’s calories came from carbs, from fats,
and from protein?
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