Activity 2 – How much am I supposed to eat?

In this lesson, students compare serving sizes with portions, and discover their personal energy requirements through the integration of math and technology. In the end, students will understand diets are as individual as people.

Learning outcomes

Students will:

• Understand the difference between a serving size listed on a food label and an actual portion.
• Calculate the difference in calories between a standard serving size and an actual portion.
• Utilize the basic information on food labels to make decisions about the nutritional value of various foods.
• Develop flexibility in solving problems by selecting strategies and using mental computation, estimation, calculators, or computers, and paper and pencil.

Teacher planning

Time required

Two 40–60 minute class periods

Materials needed

• Chart paper
• Chart markers
• Poster of example nutrition label
• Calculators
• For each pair of students:
  • 1 cereal bowl
  • 1 box of cereal with nutrition labels removed (keep labels) or covered
  • 1-cup measure

Technology resources

• Computers with Internet access
• Printer
• Optional: Graphing software

Pre-activities

Optional: Watch the two-minute video from Discovery Health “What is a Calorie?” (The video is prefaced with a short advertisement.)

Activities

1. Begin by reviewing what students have already learned regarding diets and nutrition. Refer to charts made during the lesson Are You on a Diet? as needed. Remind students that diets are made up of foods which are made up of nutrients. Every nutrient does something for our bodies.
2. Next, tell them that diet is not just about what you eat but how much you eat. While some diets call for people to restrict or cut back on certain foods, some call for people to restrict how much is eaten. Why might someone want to restrict how much they eat? Accept all appropriate answers.
3. Tell students that there is a certain amount a person should eat each day all together and a certain amount of certain types of foods. In order to be healthy one must take into account both.
4. Then, display the poster of the example nutrition label. Explain that the nutrition label gives us information to help us determine what we are eating and whether we are eating the correct amount.
5. Tell students that over the next few lessons they will be exploring the various parts of the nutrition label. One of the first things listed is the serving size. This tells us how much of this food the manufacturer or maker recommends that you eat. The rest of the information on the label is based on the serving size.

   The label also tells you the calories in the food. Calories are how scientists measure how much energy a food has. The average adult needs about 2000 calories a day — the calories are used by the body to carry out its processes: breathing, walking, thinking, blinking, digesting, etc.

6. Have students write down the Question of the Day and make predictions as to how many calories they think they need in one day and how much cereal they think they eat in terms of cups.
7. Now students need to go to the ChooseMyPlate website to determine energy needs.

   Before going on to the website you may want to explain to students that ChooseMyPlateis simply a plan for eating created by the United States Department of Agriculture to help citizens of the United States. The plan website has a module that can help students determine how much of each food group to eat as well as the number of calories they should have per day.

   

8. Once student have received information, please print it out for later use. You may want to print two in case one is misplaced.
9. Ask students to compare what they are supposed to have to their predictions. Discuss observations and conclusions.
10. Ask, “Do you think it’s easy to eat the right amount each day? What might happen if we don’t?” Lead a discussion on why calorie counting is important. Tell students the way that most people overeat but they don’t know it because they do not pay attention to the recommended serving size.
11. (This is a good stopping point if doing this lesson in two days.) Ask, “How many of you pay attention to the serving sizes? Who thinks they are eating the serving size when eating chips? Steak? Cereal?”
12. (Cereal is notorious for being overeaten) Tell students they will be determining how many calories are in their usual serving of cereal versus what the recommended serving size is.
13. Then, have students create a chart in their science journals/notebooks like the one below.
    

    Cereal Name:	Measurement	Calories	Difference	What does this mean for me?
    Amount I Eat
    Recommended Serving Size (RSS)

14. Have students gather materials at their work area in pairs.
15. First, instruct one student from each pair to pour an amount of cereal he/she would normally eat for breakfast, measure the amount, and record it in the data chart. Repeat with the other student.
16. Second, ask students to uncover the nutrition label, or give back the corresponding nutrition label for each cereal.

    Third, have students record the measurement of the serving size in the data chart as well as the calories per serving. Ask students to brainstorm ways to calculate the number of calories in their personal portions, and the difference between the total number of calories. Assist students with calculations as necessary.

17. Note: In order to do this, students will need to first figure the calories per gram by dividing the number of calories by the number of grams in the RSS. The, multiply the per gram calorie amount by the total number of grams eaten. Example: Serving size 1 slice (26 g) = 60 calories
    60 ÷ by 26 = 2.3 calories per gram
    Actual serving size = 42 g × 2.3 = total calories in serving
18. Lead a discussion on student conclusions from this trial. Tell them that what they really eat is called a portion. Ask, “What is the difference between a portion and a serving size? How many servings were in your portion? What effects may this have?”
19. Optional: Students may make a double-bar graph on paper or computer to further illustrate the differences between portion and serving size. This may also extend to a lesson on inequalities.
20. Tell students that most organisms somehow “know” how much to eat, yet humans need a little help. The label tells how much the maker of the product thinks the normal person will eat. Yet is important to know what this means because it can help us determine what is in our portions. It also helps us keep track of what we are eating. Ask, “How else might knowing the serving size help us with our diets?” Accept and discuss all appropriate responses.
21. Review determining how many calories their portions had. Tell students this is the same way that to calculate the amount of nutrients in a certain food. Tell students, “Compare the serving size on the label with what you actually ate, or your portion. You must do some math. For example, 1 potato has four grams of protein, but if you ate five potatoes, you would have eaten five times that much or twenty grams.”
22. Give students the Serving Size Math worksheet and allow them to work in pairs to practice this skill.
23. Once students have finished, you may review worksheet and briefly explain the My Pyramid Plan as simply the diet for normal, everyday folks.
24. Have students discuss and compare their energy needs versus what they received just from the cereal. What are some implications? Are the cereals healthy? Why or why not? What other foods are usually overeaten? Why?
25. Tell students that now that they know how much they are supposed to eat, they will be finding out what is in the food they eat and why they must eat a certain amount.
26. To close, direct students to these essential questions:
    • What is nutrition?
    • How much am I supposed to eat?
    • What happens when you eat too much or not enough?
    • What does it mean to be a healthy eater?
    • Are you on a diet?

    Have short discussion to review essential understandings for this activity and add student ideas to essential questions charts.

27. Allow students a few minutes to reflect on and answer the QOD.

Assessment

• Assess student data charts from cereal investigation.
• Consider student responses during discussions and brainstorming, and to essential questions.
• Students should record an answer to the QOD in their science notebooks that correctly applies essential understandings of the activity.
• The Serving Size Math worksheet should be evaluated.

Modifications

• While it would be ideal to have a variety of cereals, no cereal is needed at all. Students may use other types of foods commonly overeaten (chips, nuts, candy).
• If time is an issue, students do not have to make the chart. An interactive class chart can be made or a chart template can be copied ahead of time for each student.
• Calculators may be used for the Serving Size Math worksheet.
• Watch the video National Body Challenge: Portion Control (prefaced by an advertisement). Students may create a list of recommendations to help people be mindful of serving sizes. These can also be in poster form and hung in the school cafeteria and/or staff lounge.
• The size of the plate or bowl has been correlated with the size of the serving. Begin the investigation by using different size bowls and discuss any implications. Explore if the cereal type may also lead to overeating (size, flavor, etc.).

Home-based activity

Students can conduct the cereal investigation at home with their families and share results, conclusions, and next steps with the class the next day.

Alternative assessments

• If necessary, a student’s answers to the various assessment tools can be given orally and/or dictated to a scribe.
• Calculator usage may be forbidden.
• Higher achieving students may be given this activity to complete independently, while low achieving students may need to work in small groups and/or directly with the teacher.
• Students may be given only one half (top or bottom) of the Serving Size Math worksheet.

Supplemental information

If computer access is not available or limited, use the following guidelines:

Girls ages 9 to 13

Calories	1,600 to 2,200; could be greater depending on age, growth and activity level
Protein	10% to 30% of daily calories
Carbohydrates	45% to 65% of daily calories (at least 130 grams)
Total fat	25% to 35% of daily calories
Sodium	1,500 milligrams a day
Fiber	26 grams a day
Calcium	1,300 milligrams a day

Boys ages 9 to 13

Calories	1,800 to 2,600; could be greater depending on age, growth and activity level
Protein	10% to 30% of daily calories
Carbohydrates	45% to 65% of daily calories (at least 130 grams)
Total fat	25% to 35% of daily calories
Sodium	1,500 milligrams a day
Fiber	31 grams a day
Calcium	1,300 milligrams a day

Critical vocabulary

• nutrition
• nutrients
• diets
• label
• facts

serving size

the amount the average person is expected to eat; the basis for the information found on the nutrition facts label

portion

the amount a person usually eats

North Carolina curriculum alignment

Healthful Living Education (2006)

Grade 4

• Goal 4: The learner will apply knowledge and behavior self management skills to areas of nutrition and physical activity for healthy growth, development, and maintenance.
  • Objective 4.03: Utilize the basic information on food labels to make decisions about the nutritional value of various foods.

Mathematics (2004)

Grade 4

• Goal 1: Number and Operations - The learner will read, write, model, and compute with non-negative rational numbers.
  • Objective 1.02: Develop fluency with multiplication and division:
    • Two-digit by two-digit multiplication (larger numbers with calculator).
    • Up to three-digit by two-digit division (larger numbers with calculator).
    • Strategies for multiplying and dividing numbers.
    • Estimation of products and quotients in appropriate situations.
    • Relationships between operations.
  • Objective 1.05: Develop flexibility in solving problems by selecting strategies and using mental computation, estimation, calculators or computers, and paper and pencil.

Science (2005)

Grade 4

• Goal 4: The learner will conduct investigations and use appropriate technology to build an understanding of how food provides energy and materials for growth and repair of the body.
  • Objective 4.01: Explain why organisms require energy to live and grow.
  • Objective 4.02: Show how calories can be used to compare the chemical energy of different foods.
  • Objective 4.03: Discuss how foods provide both energy and nutrients for living organisms.

Note: Survey students as to their favorite cereals. Buy generic equivalents of popular name brand cereals to save money or solicit donations from parents, PTA, or local businesses. Supermarkets may be willing to donate boxes of cereal that are out of date. English language learners often have food items at home with nutrition facts labels in their native language. Ask them to bring these in ahead of time.