Food and Exercise: Calories In – Work Out


Students learn to see food as fuel for cellular and physical work and compare the number of calories in food with the number required for work. They observe how a fatty meal leads to fat in the blood stream.


  • Students are introduced to the concept of food as fuel for energy.
  • Students learn that the amount of energy stored in food is measured in calories.
  • Students understand that food must be digested in order to provide building blocks and energy for cells.
  • Students compare the energy in food with the energy required to perform everyday and athletic activities.
  • Students understand how exercise helps the body to work better.

Curriculum Topics:

Life Science, Anatomy, Nutrition, Exercise, Digestion

Grade Level:
6 - 12

Estimated Time:
2 – 3 class periods

Lesson Plan:

  1. Eating – it's something we all do every day. Why do we eat? Gather some ideas from a brief class discussion. There are many reasons; because we are hungry, or we are bored, or it is the right time of day, or because it makes us happy or because it is social – but the real underlying reason we eat is because need to fuel our bodies. We need food to provide the building blocks animals require to repair our bodies and to build new cells and we need energy to power all the reactions in our bodies that allow us to breathe, think, move, and survive. In order to use food as energy or as building material is must first be broken down and digested into molecules that can be carried in the blood to every cell in our body.

  2. Show the PBS LearningMedia video Food is Fuel (4 minutes).

  3. Classroom activity or homework: Print the student handout Food is Fuel Crossword Puzzle from the Food is Fuel resource and a copy of the Food is Fuel Word List (supplemental material PDF) for each child. Allow time for students to answer the crossword questions.

    Students have learned that:
    • food is fuel for the body.
    • food we eat is digested and provides energy for every cell in the body.
    • we measure the energy provided by food in calories.

  4. Remind the class that everything we eat contains calories and everything we do uses calories. Even when we are sleeping our bodies are using energy to keep us alive; to pump blood, to inflate our lungs, to move food through our guts and digest it.

    In order to be healthy, there has to be a balance between what we eat (energy in) and the work our body does (energy used). The body is excellent at conserving energy. If we eat more calories than we use to fuel our cells, the body saves that extra energy as fat. It is important for athletes to know how much energy they are using in training so that they can be sure they are eating enough to fuel their training and make their bodies work efficiently.

  5. Briefly lead a discussion of what kinds of food have a lot of calories and what kinds of food have fewer calories. This might be a good time to remind students that calories are not the only thing to think about when we eat – individual nutrients are very important too. This lesson however focuses on energy, which is measured in calories.

    We all know that when we exercise we use more energy, or calories, than when we are sitting at a desk, for example, but the human body is incredibly efficient. Sometimes it is surprising how few calories we are using.

  6. Lead a class discussion and ask the students to guess how many calories are used in some common activities. Choose examples relevant to your class from one of the many sites on the web or use the examples below from Remind the students that a bigger person will use more calories than a smaller person when they are doing the same amount of work for the same amount of time, so weight must be taken into account when calculating calories used. The examples below are for a 130 lb person.

    Brushing teeth for 3 minutes – 7 calories
    Grocery shopping for 20 minutes – 70 calories
    Playing basketball for 20 minutes – 117 calories
    Walking the dog for 20 minutes – 86 calories
    Jogging for 20 minutes – 195 calories
    Swimming for 20 minutes – 174 calories
    Shoveling snow for 20 minutes – 117 calories

  7. Show the PBS LearningMedia video The Truth About Exercise: Calories and Fat Deposits (7.2 minutes). In this BBC video, Michael Mosley learns some surprising things about the calories in his breakfast and how many calories he uses running around a track. He also learns about how fat in food affects his blood.

  8. Facilitate a class discussion about what students learned from this video and what they found surprising about the information presented.

    One of the important points in this video is that exercise is not necessarily about losing weight. It is beneficial because it helps the body work more efficiently.

  9. Show the PBS LearningMedia video How the Body Responds to Exercise (5.3 minutes).This video explains in scientific terms how the bodies of runners change as they prepare to run their first Boston Marathon.

  10. Discuss the changes in arteries and veins, capillary number and mitochondria that occur as the athletes put more demands on their bodies during their marathon training. Explain any terms which might be new to the students. Allow the class to share their reactions to the video. Emphasize that all exercise makes the body work better.

Individual or Class Activity:

  • Ask the students to write down everything they ate for lunch. If students have access to computers ask them to use the USDA calculator at to calculate how many calories their lunch contained. Once they have calculated the lunch number ask them to find an example of an activity that would use approximately the same number of calories. They could use the following web site or another of your choice.
    If students do not have access to computers, this activity could be a class exercise using the teacher's computer for food values. It might be interesting to include some of the school lunch options in these calculations. A list of everyday and athletic activities with approximate calorie counts could be provided and the students could identify the closest match to one or several lunch options.
  • Allow the students to share their reactions to the results of this activity.

Additional or Closing Activities:
Students draw small posters illustrating a lunch and the activity that would use the same number of calories. Posters are displayed in the classroom as a visual reminder of the relationship between calories consumed and the work which they fuel.
Athletes in the class might be interested to work out how many calories they burn in a typical practice session or game.

PBS LearningMedia Resources:

Supplemental Material:

Food is Fuel Word List PDF

Related PBS LearningMedia Resources:

Other Resources:

Common Core Standards:
6A/M1 (Grades: 6-8): Like other animals, human beings have body systems for obtaining and deriving energy from food and for defense, reproduction, and the coordination of body functions.
6C/M1 (Grades: 6-8): Organs and organ systems are composed of cells and help to provide all cells with basic needs.
6C/M2 ( Grades: 6-8): For the body to use food for energy and building materials, the food must first be digested into molecules that are absorbed and transported to cells.
6C/H6 (Grades: 9-12): The human body is a complex system of cells, most of which are grouped into organ systems that have specialized functions. These systems can best be understood in terms of the essential functions they serve for the organism: deriving energy from food, protection against injury, internal coordination, and reproduction.


Lesson Contributed by Lindsey Panton.

For a demonstration or more details, contact Karen Karst-Hoskins
at or call 775.682.7805 or 775.544.9061.

Funding provided by NV Energy and the Walmart State Giving Program.