Food provides the body with materials for growth, repair of tissues, and energy. It also helps maintain homeostasis. There are six groups of nutrients: carbohydrates, fats, proteins, vitamins, minerals, and water. Calories measure the energy in foods, with one Calorie equaling 1,000 calories. Carbohydrates and fats are the body's primary sources of energy. Proteins are needed for tissue growth and repair. Vitamins and minerals help the body carry out processes, though they do not provide energy. A balanced diet with a variety of foods can provide all necessary nutrients. Food labels allow people to make informed choices about their nutrition.

1. Ranya Sharaf pd# 2
Title: Food and Energy 15.1
Why you need food
What does food provide your body Food provides your body with materials for growing and for repairing tissues.
with? Food also provides energy for everything you do.
Ex). Running, playing a musical instrument, reading, and even sleeping require
energy.
How does food help your body? With Food also helps your body maintain homeostasis, or a stable internal
what? environment.
Nutrients
What are nutrients? Your body breaks down the foods you eat to nutrients.
Nutrients are the substances in food that provide the raw materials and energy
What are the six groups of nutrients? the body needs to carry out all its essential processes.
There are six groups of nutrients necessary for human health—carbohydrates,
fats, proteins, vitamins, minerals, and water.
Energy
What are calories? When nutrients are used by a body for energy, the amount of energy they
release can be measured in units called calories.
What is one calorie equal to? One calorie is the amount of energy needed to raise the temperature of one
gram of water by one degree Celsius.
What is one Calorie equal to? Biologists use the term Calorie to measure the energy in foods. One Calorie is
What is an example of the use of the same as 1 kilocalorie (kcal) or 1,000 calories.
Calories? Ex). One serving of popcorn may contain 60 Calories (60 kcal), or
60,000 calories, of energy.
More calories= more energy
How does the rate of calories a person You need to eat a certain number of Calories each day to meet your body’s
need change over years/ time? energy needs. Your daily energy requirement depends on your level of physical
activity. When you were a child, you grew very rapidly, so you were likely to
have had very high energy needs. Your current growth and level of physical
activity affect the number of Calories you need now. The more active you are=
the greater your energy needs are.
Carbohydrates
What are carbohydrates? The nutrients called carbohydrates which are composed of carbon, oxygen,
What is the rate of carbohydrates and hydrogen, are a major source of energy.
compared to Calories? One gram of carbohydrate provides your body with four Calories of energy.
*important* In addition to providing energy, carbohydrates provide the raw materials to
make cell parts.
How are carbohydrates divided? Based on their chemical structure, carbohydrates are divided into simple
carbohydrates and complex carbohydrates.
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2. Simple Carbohydrates
What is glucose? Simple carbohydrates = sugars. One type of sugar called glucose is the major
source of energy for your body’s cells.
How does the body make glucose from most foods do not contain large amounts of glucose. The body converts other
other sugars? types of sugars, like the sugar found in fruits, into glucose.
Glucose is the form of sugar the body can easily use.
Complex Carbohydrates
What complex carbohydrates made Complex carbohydrates are made up of many sugar molecules linked together
of? in a chain. Ex). Starch is found in foods from plants, like potatoes, rice, wheat,
How does the body use starch? and corn.
How does the body use fiber? To use starch for energy, first your body breaks it down into smaller sugar
molecules. Then your body will have the ability to let out the molecules’
energy.
Fiber is a complex carbohydrate found in plants, like starch. But fiber cannot be
broken down into sugar molecules by your body. So, fiber passes through the
body and is soon gets eliminated over time.
Since your body cannot digest fiber it is not considered a nutrient.
Fiber is still an important part of the diet, because it helps keep the digestive
system functioning properly.
Nutritionists’ Recommendations
How do complex carbohydrates differ Nutritionists recommend that 45 to 65 percent of the Calories in a diet come
from simple carbohydrates? from carbohydrates. It is better to eat complex carbohydrates, like whole
grains, than simple carbohydrates.
Why are complex carbohydrates Foods made with whole grains usually contain a variety of other nutrients.
better? Foods with lots of sugar, such as candy and soft drinks, have few valuable
nutrients. Also, while sugars can give you a quick spring of energy, starches
provide a more long-term energy source.
Fats
What are fats? Fats are energy-containing nutrients that are composed of carbon, oxygen, and
hydrogen. However, fats contain more than twice the energy of an equal
amount of carbohydrates. One gram of fat provides your body with nine
Calories of energy.
Kinds of Fats
How are fats classified? Fats may be classified by unsaturated or saturated based on their chemical
What are unsaturated fats? structure. Unsaturated fats are usually liquid at room temperature.
Ex).Most cooking oils are unsaturated fats.
What are saturated fats? Saturated fats are usually solid at room temperature.
Ex).Meat and dairy products contain relatively large amounts of saturated fat.
What are trans fats? Trans fats are made when manufacturers add hydrogen to vegetable oils.
Foods containing trans fats stay fresh longer than foods containing unsaturated
What kind of fat is most healthful? fats. Ex).found in margarine, chips, and commercially baked goods.
Both trans fats and saturated fats are considered to be less healthful than
unsaturated fats.
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3. *important* In addition to providing energy, fats have other important functions. Fats form
part of the cell membrane, the structure that forms the boundary of a cell.
Fatty tissue protects and supports your internal organs and insulates your
body.
Cholesterol
What is cholesterol? Cholesterol is a waxy, fatlike substance found only in animal products.
Cholesterol is an important part of your body’s cells.
Your liver makes all of the cholesterol your body needs. So, cholesterol is not a
necessary part of the diet.
Nutritionists’ Recommendations
Why should we not eat too many fats? They recommend that no more than 30 percent of the Calories eaten each day
come from fats. Extra fats and cholesterol in a diet can lead to a buildup of
fatty material in the blood vessels. This will then cause heart disease.
Proteins
What are proteins? Proteins are nutrients that contain nitrogen as well as carbon, hydrogen, and
oxygen. Proteins can serve as a source of energy, but they are a less important
source of energy than carbohydrates or fats. About 10 to 35 percent of your
daily Calorie intake should come from proteins.
*important* Proteins are needed for tissue growth and repair. They also play an important
part in chemical reactions within cells.
Amino Acids
What are amino acids? Proteins are made up of small units called amino acids, these are linked
together chemically to form large protein molecules.
Thousands of different proteins are built from only about 20 different amino
What are essential amino acids? acids. Your body can make about half of the amino acids it needs.
The others, called essential amino acids, must come from the foods you eat.
Complete and Incomplete Proteins
What are complete proteins? Foods from animals, like meat and eggs, are sources of complete proteins
because they contain all the essential amino acids.
What are incomplete proteins? Proteins from plants, such as beans, grains, and nuts, are called incomplete
How could a person obtain all proteins because they are missing one or more essential amino acid.
essential amino acids? Different plants lack different amino acids. So, to obtain all the essential amino
acids from plants alone, people need to eat a large variety of plant foods.
Vitamins and Minerals
What are the two kinds of nutrients? There are two kinds of nutrients, vitamins and minerals. They are needed by
the body in very small amounts.
How are they different then other Not like other nutrients, vitamins and minerals do not provide the body with
nutrients? energy or raw materials. Instead, they help the body carry out processes.
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4. What are vitamins? Vitamins act as helper molecules in a variety of chemical reactions in the body.
What are some examples of vitamins? Ex).Vitamin K helps your blood to clot when you get a cut or a scrape.
The body can make a few of these vitamins.
Ex).your skin can make vitamin D when exposed to sunlight.
Most vitamins, however, must be obtained from foods.
Fat-Soluble and Water-Soluble Vitamins
How are vitamins classified? Vitamins are classified as either fat-soluble or water-soluble.
Fat-soluble vitamins dissolve in fat, and they are stored in fatty tissues in the
body. Ex).
What are fat- soluble vitamins? Vitamins A, D, E, and K are all fat-soluble vitamins. Water-
Examples? soluble vitamins dissolve in water and are not stored in the body.
What are water- soluble vitamins? Ex). This fact makes it especially important to include sources of water-soluble
Examples? vitamins—vitamin C and all of the B vitamins—in your diet every day.
Importance of Vitamins
Although vitamins are only needed in small amounts, a lack of certain vitamins
in the diet can lead to health problems.
How are vitamins so important? In the 1700s, sailors on long voyages survived on hard, dry biscuits, salted
meat, and not much else. Because of this limited diet, many sailors developed
a serious disease called scurvy. People with scurvy suffer from bleeding gums,
How did James Lind find how to cure stiff joints, and sores that do not heal. Some may even die.
the disease? A Scottish doctor, James Lind, created a hypothesis that scurvy was the result
What did he recommend for the of the sailors’ poor diet. Lind divided sailors with scurvy into groups and fed
sailors? different foods to each group. The sailors who were fed fruits of oranges and
The lack of what vitamins cause lemons recovered from the disease. Lind recommended that all sailors eat
scurvy? citrus fruits. When Lind’s recommendations were carried out, scurvy
disappeared. Today scientists know that scurvy is caused by the lack of vitamin
C, which is found in citrus fruits
Importance of Minerals
What are minerals and how do you Nutrients that are not made by living things are called minerals. Minerals are
obtain them? present in soil and are absorbed by plants through their roots. You obtain
minerals by eating plant foods or animals that have eaten plants.
Ex). Many know that calcium is needed for strong bones and teeth. Iron is
needed for the proper functioning of red blood cells.
*important* Both vitamins and minerals are needed by your body in small amounts to carry
out chemical processes
What is the best way to receive all If you eat a wide variety of foods, you probably will get enough vitamins and
your needed vitamins and minerals? minerals. Most people who eat a balanced diet do not need to take vitamin or
mineral supplements.
Water
Although people can probably survive for weeks without food, they will die
How much water does the body within days without fresh water. Water is the most abundant substance in the
contain? body. It contains for about 65 percent of the average person’s body.
*important* Water is the most important nutrient because the body’s processes including
chemical reactions such as the breakdown of nutrients take place in water.
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5. Summary:
How is water important to the blood in All the cells in your body are composed mostly of water. Water makes up most
your body? of the body’s fluids, including blood. Nutrients and other important substances
are carried throughout the body dissolved in the watery part of the blood. The
water in blood also carries waste that must be removed from your body.
What is perspiration? Perspiration contains chemicals dissolved in water. The water in perspiration
comes from body tissues. Sweat glands in your skin release the water on the
What does perspiration do? surface of your body. Perspiration helps regulate body temperature by cooling
the body.
How much water does a person need? Under normal conditions, you need to take in about 2 liters of water every day.
The more you perspire the more water you need. You can obtain water by
What are some foods you could get drinking water and other beverages. Fruits and vegetables such as melons and
water from? tomatoes have a large amount of water.
The Food Guide Pyramid
*Important* The Food Guide Pyramid classifies foods into six groups. It also indicates how
many servings from each group should be eaten every day to maintain a
healthy diet. You can use the pyramid’s guidelines and your own food
preferences to have a healthy diet containing foods you like.
Food labels
*important* Food labels allow you to evaluate a single food as well as to compare the
nutritional value of two different foods.
What should you look for on food 1. Serving Size This information tells you the size of a single serving and
labels? the number of servings in the container. The information on the rest of
the label is based on serving size. If you eat twice the serving size, then
you’ll consume twice the number of Calories.
2. Calories This information tells you how much energy you get from one
serving of this food, including how many Calories come from fat.
3. Percent Daily Value The percent daily value shows you how the
nutritional content of one serving fits into the recommended diet for a
person who consumes 2,000 Calories per day. For example, one
serving of this cereal contains 12° of the total amount of sodium a
person should consume in one day. You might eat more or less than
2,000 Calories per day. But, you can still use this percentage as a
general guide.
4. Ingredients The ingredients are listed in order by weight, starting with
the main ingredient. The list can alert you to substances that have
been added to a food to improve its flavor or color, or to keep it from
spoiling. In addition, reading ingredients lists can help you avoid
substances that make you ill.
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6. Using Food Labels
How are food labels useful? Food labels can help you make healthful food choices.
What is an example of the use of food By reading the labels, you might find that one cereal contains little fat and a
labels? high percentage of the Daily Values for complex carbohydrates and several
vitamins. Another cereal might have fewer complex carbohydrates and
vitamins, and contain significant amounts of fat. So you now know that the first
cereal would be a better choice as a regular breakfast food.
Dietary Reference Intakes
What are dietary reference intakes? Food labels can also help you monitor the nutrients in your diet. Guidelines
that show the amounts of nutrients that are needed every day are known
as Dietary Reference Intakes (DRIs).
Ex). The DRIs for vitamins recommend that people your age get 45 milligrams
What is an example of one? of vitamin C every day.
DRIs also show how the Calories that people eat each day should be split
What do DRIs show or determine? among carbohydrates, fats, and proteins. The Percent Daily Values listed on
food labels can help you make sure that you are meeting the DRIs for different
nutrients.
Summary:
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© 2004 AVID Center. All rights reserved.

7. Using Food Labels
How are food labels useful? Food labels can help you make healthful food choices.
What is an example of the use of food By reading the labels, you might find that one cereal contains little fat and a
labels? high percentage of the Daily Values for complex carbohydrates and several
vitamins. Another cereal might have fewer complex carbohydrates and
vitamins, and contain significant amounts of fat. So you now know that the first
cereal would be a better choice as a regular breakfast food.
Dietary Reference Intakes
What are dietary reference intakes? Food labels can also help you monitor the nutrients in your diet. Guidelines
that show the amounts of nutrients that are needed every day are known
as Dietary Reference Intakes (DRIs).
Ex). The DRIs for vitamins recommend that people your age get 45 milligrams
What is an example of one? of vitamin C every day.
DRIs also show how the Calories that people eat each day should be split
What do DRIs show or determine? among carbohydrates, fats, and proteins. The Percent Daily Values listed on
food labels can help you make sure that you are meeting the DRIs for different
nutrients.
Summary:
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© 2004 AVID Center. All rights reserved.