Lesson 3 of 9

Energy in food

Goal: Calculate energy needs and compare foods.

Puzzles for this lesson

Food is your body’s fuel. The energy in food is measured in kilojoules (kJ).

The energy in 100 g of each food in the picture.

Different foods have different energy values. A food label gives the energy in 100 g, so that you can compare them.
Lipids hold the most energy. 1 g of lipid has about twice as much energy as 1 g of carbohydrate or protein.
Your needs depend on your age and on how active you are. You use energy all the time, even asleep, to keep warm, to grow and to keep your heart beating. Moving uses more.

Your turn

This lesson’s activity starts here in a moment.

I can read energy values in kilojoules.I can explain why needs change with age and activity.I can total the energy in a day’s food.

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Carbohydrate The body’s main source of energy: starch and sugars

Lipid A fat or an oil, which the body can store for energy

Protein The nutrient used to build new tissue for growth and repair

Kilojoule The unit of energy on a food label

For teachers: AQA 3.8.4 · Pearson Edexcel 5.4, 5.5 · Cambridge 8Bp.02 in part