Food and Energy

1
Table of Contents

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

2
Why You Need Food

• Food provides your body with materials for
  growing and for repairing tissues. Food also
  provides energy for everything you do!
• Food also helps your body maintain homeostasis

3
Nutrients

• Your body breaks down the food that you eat
  into nutrients
• Nutrients are the substances that provide the raw
  materials and energy the body needs to carry out
  all its essential processes
• There are six groups of nutrients that are
  essential for human health
• Carbohydrates
• Fats
• Proteins
• Minerals
• Vitamins
• Water

4
Energy

• When nutrients are used by the body for energy,
  the amount of energy they release can be measured
  in units called calories
• One calorie is the amount of energy needed to
  raise the temperature of one gram of water by one
  degree Celsius
• 1 Calorie 1 kilocalorie (kcal) 1000
  calories
• Ex 1 serving of popcorn 60 Cal 60,000 cal
  60 kcal
• You need a certain number of Calories each day
  to meet your bodys needs
• Your bodys needs depend on your level of
  physical activity and your age

5
Carbohydrates

• Carbohydrates made of carbon, hydrogen and
  oxygen are a major source of energy
• 1g of carbohydrate 4 Calories of energy

6
Carbohydrates
- Food and Energy

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

7
Types of Carbohydrates

• Based on their chemical structure, carbohydrates
  are divided into simple carbohydrates and complex
  carbohydrates
• Simple Carbohydrates aka sugars (or glucose)
• Major source of energy for your bodys cells
• Ex sugar found in fruits, candies, cakes
• Complex Carbohydrates
• Made of many sugar molecules linked together in a
  chain
• Ex potatoes, rice, wheat, and corn, starch,
  fiber
• Your body must break these down into individual
  sugar molecules to process and use for energy

8
Nutritionist Recommendations

• 45-65 of the Calories in a diet should come
  from carbohydrates
• It is better to eat complex carbohydrates (like
  whole grains) instead of simple carbohydrates
  (like soda, candies, and any food containing lots
  of sugar)

9
Fats

• Fats energy-containing nutrients that are
  composed of carbon, hydrogen, and oxygen
• 1 gram of fat 9 Calories of energy
• In addition to providing energy, fats have other
  important functions
• Fats form part of the cell membrane, the
  structure that forms the boundary of the cell.
• Fatty tissue protects and supports your internal
  organs
• Fats insulate your body

10
Fats
- Food and Energy

• Many foods contain saturated, unsaturated, and
  trans fats. Unsaturated (usually liquid at room
  temperature) fats are considered to be more
  healthful than saturated fats and trans fats.

11
Cholesterol

• Cholesterol is a waxy, fat-like substance found
  only in animal products
• Important part of your bodys cells
• However, your liver can make all the
  cholesterol your body needs so it is not
  necessary to incorporate this into your diet

12
Nutritionist Recommendations

• No more than 30 of the Calories eaten each day
  come from fats
• A diet high in fat and cholesterol can lead to
  a build up of fatty material in the blood vessels
  and cause heart disease

13
Proteins

• Proteins nutrients that contain nitrogen,
  carbon, hydrogen and oxygen
• Function of Proteins in the Body
• Proteins are needed for tissue growth and
  repair
• Play an important role in the chemical
  reactions that happen in our body
• Can serve as source of energy however they are
  less important sources of energy than
  carbohydrates and fat
• 10-35 of your daily Calorie intake should come
  from proteins

14
Amino Acids

• Proteins are made of small subunits called amino
  acids
• Amino acids are linked together to make large
  protein molecules
• Thousands of different proteins are built from
  about 20 different amino acids
• Your body can make about half of the amino acids
  it needs. All the rest (essential amino acids)
  must come from the food we eat

15
Complete and Incomplete Proteins

• Complete Proteins
• animal sources such as meat and eggs
• contain all the essential amino acids
• Incomplete Proteins
• come from plants, beans, grains, nuts
• Incomplete because they do not contain all
  essential amino acids
• Vegetarians must eat a wide variety of plants,
  beans and grains to ensure they get all the
  essential amino acids in their diet

16
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

17
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

18
Vitamins and Minerals

• Vitamins and minerals are needed by the body in
  very small amounts.
• Vitamins and minerals do not provide the body
  with energy
• Vitamins and minerals help the body carry out
  essential processes

19
Vitamins
- Food and Energy

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

20
Fat Soluble and Water Soluble Vitamins

• Fat-Soluble Vitamins
• dissolve in fat
• stored in fatty tissues in the body
• Vitamins A, D, E and K
• Water Soluble Vitamins
• dissolves in water
• not stored in the body
• Important to include these in your everyday
  diet
• Vitamins C and B

21
Importance of Vitamins

• Lack of certain vitamins can lead to health
  problems
• Scurvy
• Symptoms bleeding gums, stiff joints, sores that
  do not heal
• Cause Lack of Vitamin C

22
Minerals
- Food and Energy

• Nutrients that are not made by living things are
  called minerals.
• Plants absorb minerals through their roots and we
  obtain minerals through eating those plants

23
Water

• Water is the most important nutrient because the
  bodys vital processes - including chemical
  reactions such as the break down of nutrients
  take place in water.
• Carries nutrients throughout the body
• Temperature regulation (sweat)
• Removes waste (urination and sweat)
• Need about 2 Liters of water a day

24
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.

25
Links on Food and Energy
- Food and Energy

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

26
End of SectionFood and Energy
27
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.

28
Learning Objectives

• Describe/Explain how the food pyramid can help
  plan a healthy diet
• Describe/Identify the types of information that
  is included on food labels

29
The Food Guide Pyramid

• Classifies food into 6 groups. It also indicates
  how many servings from each group should be eaten
  every day to maintain a healthy diet

30
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.
31
Using Food Labels

• Help you make better choices when you decide
  what to eat
• Compare Snack Food Labels at your table and as
  a group decide which would be better for you and
  why

32
Complete the Skills Activity on pg 57
33
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
34
End of SectionHealthy Eating
35
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.
• The organs of the digestive system are about 9
  meters long from beginning to end

36
Digestion

• Digestion ? The process by which your body breaks
  down food into small nutrient molecules (atoms
  chemically bonded together)
• 2 Kinds of Digestion
• Chemical chemicals produced by the body break
  food into smaller pieces Ex bread? sugar
  molecules
• Mechanical broken down into smaller pieces

37
Absorption and Elimination

• Absorption ? process by which nutrient molecules
  pass through the wall of your digestive system
  into your blood
• Materials that are not absorbed are eliminated
  from the body as wastes

38
The Mouth
- The Digestive Process Begins

• Both mechanical and chemical digestion begin in
  the mouth.

39
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.

40
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.

41
Protein Digestion
- The Digestive Process Begins

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

• Percentage of egg white digested

42
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

43
Protein Digestion
- The Digestive Process Begins

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

• About 70

44
Protein Digestion
- The Digestive Process Begins

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

• From 13 to 16 hours

45
The Esophagus

• There are two openings at the back of your mouth
• One for your windpipe
• One for food to go to the stomach
• Epiglottis ? a flap of tissue that prevents food
  from entering your windpipe and directs food to
  the
• Esophagus ? muscular tube lined with mucus that
  connects the mouth to the stomach
• Peristalsis ? Systematic muscle contractions of
  the esophagus that push food toward the stomach

46
The Stomach
- The Digestive Process Begins

• Most mechanical digestion and some chemical
  digestion occur in the stomach. Chemical
  Digestion ? pepsin and hydrochloric acid

47
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

1. Food is digested in the stomach.

What You Learned

1. Digestion begins in the mouth.

48
Digestion
- The Digestive Process Begins

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

49
Links on Digestion
- The Digestive Process Begins

• Click the SciLinks button for links on digestion.

50
End of SectionThe Digestive Process Begins
51
The Small Intestine
- Final Digestion and Absorption

• The small intestine is the part of the digestive
  system where most chemical digestion takes place.
  Almost all nutrient absorption takes place in the
  small intestine

52
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.

53
The Liver

• Upper right portion of the abdomen
• The role of the liver in the digestive system
  is to produce bile
• Bile is a substance that breaks up fat
  molecules
• Bile travels from the liver to the gall bladder
  and then to the small intestine during digestion

54
The Pancreas

• Triangular organ that lies between the stomach
  and the first past of the small intestine
• Pancreas produces enzymes that flow into the
  small intestine and help break down starches,
  proteins and fats

55
The Large Intestine

• Last section of the digestive system
• 1.5 meters long
• Contains bacteria that feed on the material
  passing through
• By the time food gets to the large intestine
  almost all nutrient absorption is complete
• Water absorption and preparing for waste
  elimination is the main function of the large
  intestine

56
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.
57
More on the Digestive System
- Final Digestion and Absorption

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

58
End of SectionFinal Digestion and Absorption
59
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.
60
End of SectionGraphic Organizer