Food and Energy

1
Table of Contents

• Food and Energy
• Healthy Eating
• The Digestive Process Begins
• Final Digestion and Absorption

2
Carbohydrates
- Food and Energy

• In addition to providing energy, carbohydrates
  provide the raw materials to make cell parts.

3
Fats
- Food and Energy

• Many foods contain saturated, unsaturated, and
  trans fats. Unsaturated fats are considered to be
  more healthful than saturated fats and trans fats.

4
Percentages
- Food and Energy

• A percentage () is a ratio that compares a
  number to 100. For example, 30 means 30 out of
  100.
• Suppose that a person eats a total of 2,000
  calories in one day. Of those calories, 300 come
  from protein. Follow these steps to calculate the
  percentage of calories that come from protein.
• 1. Write the comparison as a fraction
• 2. Multiply the fraction by 100 to express it as
  a percentage

5
Percentages
- Food and Energy

• Practice Problem
• Suppose that 540 calories of the persons 2,000
  calorie total come from fats. What percentage of
  the calories come from fats?

• 27

6
Vitamins and Minerals
- Food and Energy

• Vitamins act as helper molecules in a variety of
  chemical reactions in the body.

7
Vitamins and Minerals
- Food and Energy

• Nutrients that are not made by living things are
  called minerals.

8
Outlining
- Food and Energy
Food and Energy

• Why You Need Food
• Nutrients
• Energy
• Carbohydrates
• Simple Carbohydrates
• Complex Carbohydrates
• Fats
• Kinds of Fats
• Cholesterol
• Nutritionists Recommendations
• Proteins
• Amino Acids
• Complete and Incomplete Proteins
• Nutritionists Recommendations
• Vitamins and Minerals
• Fat-Soluble and Water-Soluble Vitamins
• Importance of Vitamins
• Importance of Minerals
• Water

• An outline shows the relationship between main
  ideas and supporting ideas. As you read, make an
  outline about the six groups of nutrients needed
  by the body. Use the red headings for the main
  ideas and the blue headings for the supporting
  ideas.

9
Links on Food and Energy
- Food and Energy

• Click the SciLinks button for links on food and
  energy.

10
End of SectionFood and Energy
11
Food Guide Pyramid Activity
- Healthy Eating

• Click the Active Art button to open a browser
  window and access Active Art about the Food Guide
  Pyramid.

12
Food Labels
- Healthy Eating

• Food labels allow you to evaluate a single food
  as well as to compare the nutritional value of
  two different foods.

1. Serving Size This information tells you the
size of a single serving and the number of
servings in the container.
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 a day.
4. Ingredients The ingredients are listed in
order by weight, starting with the main
ingredient.
13
Asking Questions
- Healthy Eating

• Before you read, preview the red headings. In a
  graphic organizer like the one below, ask a what
  or how question for each heading. As you read,
  write answers to your questions.

Healthy Eating
Question
Answer
What is the Food Guide Pyramid?
The Food Guide Pyramid classifies food into
groups to help people plan a healthy diet.
What kind of information can I find on a food
label?
Serving size, calories, Percent Daily Value, and
ingredients
14
End of SectionHealthy Eating
15
Functions of the Digestive System
- The Digestive Process Begins

• The digestive system has three main functions.
  First, it breaks down food into molecules the
  body can use. Then, the molecules are absorbed
  into the blood and carried throughout the body.
  Finally, wastes are eliminated from the body.

16
The Mouth
- The Digestive Process Begins

• Both mechanical and chemical digestion begin in
  the mouth.

17
The Mouth
- The Digestive Process Begins

• The shape of an enzyme molecule is specific to
  the shape of the food molecule it breaks down.
  Here an enzyme breaks down a starch into sugars.

18
Protein Digestion
- The Digestive Process Begins

• A scientist performed an experiment to determine
  the amount of time needed to digest protein. He
  placed small pieces of hard-boiled egg white (a
  protein) in a test tube containing hydrochloric
  acid, water, and the enzyme pepsin. He measured
  the rate at which the egg white was digested over
  a 24-hour period. His data are recorded in the
  graph.

19
Protein Digestion
- The Digestive Process Begins

• Reading Graphs
• What do the values on the y-axis represent?

• Percentage of egg white digested

20
Protein Digestion
- The Digestive Process Begins

• Interpreting Data
• After about how many hours would you estimate
  that half of the protein was digested?

• About 14 hours

21
Protein Digestion
- The Digestive Process Begins

• Interpreting Data
• How much digestion occurred in 16 hours?

• About 70

22
Protein Digestion
- The Digestive Process Begins

• Drawing Conclusions
• During which four-hour period did the most
  digestion take place?

• From 13 to 16 hours

23
The Stomach
- The Digestive Process Begins

• Most mechanical digestion and some chemical
  digestion occur in the stomach.

24
Using Prior Knowledge
- The Digestive Process Begins

• Before you read, look at the section headings and
  visuals to see what this section is about. Then
  write what you know about the digestive system in
  a graphic organizer like the one below. As you
  read, write what you learn.

What You Know

• Food is digested in the stomach.

What You Learned

• Digestion begins in the mouth.

25
Digestion
- The Digestive Process Begins

• Click the Video button to watch a movie about
  digestion.

26
Links on Digestion
- The Digestive Process Begins

• Click the SciLinks button for links on digestion.

27
End of SectionThe Digestive Process Begins
28
The Small Intestine
- Final Digestion and Absorption

• The small intestine is the part of the digestive
  system where most chemical digestion takes place.

29
The Small Intestine
- Final Digestion and Absorption

• Tiny finger-shaped projections called villi line
  the inside of the small intestine. Villi absorb
  nutrient molecules. The molecules pass from the
  villi into blood vessels.

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Identifying Main Ideas
- Final Digestion and Absorption

• As you read the section The Small Intestine,
  write the main idea in a graphic organizer like
  the one below. Then write three supporting
  details that further explain the main idea.

Main Idea
Chemical digestion takes place in the small
intestine.
Detail
Detail
Detail
Food mixes with enzymes and secretions.
Starches, proteins, and fats are digested
chemically.
Enzymes and secretions are produced by the small
intestine, liver, and pancreas.
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More on the Digestive System
- Final Digestion and Absorption

• Click the PHSchool.com button for an activity
  aboutthe digestive system.

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End of SectionFinal Digestion and Absorption
33
Graphic Organizer
In the mouth, the teeth break food into smaller
pieces and saliva begins to break down starches.
Esophagus pushes food from mouth to stomach.
In the stomach, food is churned and mixed with
digestive juices that break down protein.
In the small intestine, almost all chemical
digestion and absorption occurs.
Large intestine absorbs water and eliminates
waste.
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End of SectionGraphic Organizer