Food as fuel

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Cars cannot drive without petrol and planes cannot fly without fuel. Our bodies are no different, they need energy too.

Why do we need energy?

Everything we do uses energy. Our bodies need it to move, think and grow.

Click through the slideshow to see examples of things we need energy for.

Child walking to school in uniform

Walking to school

Our bodies need fuel to walk to and from school so it's important we eat a healthy varied diet to help power those steps.

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Where do we get energy from?

  • We get this energy from food and drinks.
  • All food releases energy when its eaten and digested.
  • The way our body is fuelled is different depending on what we eat.
  • Fast releasing foods, like grapes or jelly sweets, give us an instant quick burst of energy that does not last for long.
  • Slow releasing foods, like porridge or wholemeal bread, release energy gradually throughout the day.

Interesting words

  • listenenergy – This is what our bodies need to move, think and grow.
  • listencomplex carbohydrates – A group of healthy foods that release energy slowly. They take longer to digest so they help make your tummy feel fuller for longer. For example, brown rice, sweet potatoes and green peas are all complex carbohydrates.
  • listenprotein – A nutrient that makes our bodies strong and healthy.
  • listencalories - A calorie is a unit of energy. Just as we could measure length in centimetres, energy contained in food is measured in calories.

What is sugar?

  • Sugar comes from plants and often makes food taste sweeter.
  • It gives our bodies a big burst of energy.
  • It can be found naturally in fruits and vegetables or it can be processed, like the sugar granules some people add to their tea or coffee.
  • Although some fruits, like grapes or bananas, are full of natural sugars, they are also full of vitamins, minerals and fibre unlike sweeties.
Complex carbohydrates release energy slowly. They take longer to digest so they help make your tummy feel fuller for longer.

To be healthy we need a wide variety of food in our diets as they all provide us with different things.

Complex carbohydrates are great for slow release energy but fast releasing energy foods like fruit give us vitamins. It is all about balance.

Test your knowledge

Take a look at these two breakfast options

Archie is six, which breakfast would prepare him for a busy day at school?

Which breakfast would give Archie the most energy throughout the day?

Option two would give Archie more energy for a busy day at school.

Option 1 – Quick release food

  • For breakfast Archie eats a big bowl of sugary cereal and a glass of orange juice.
  • He gets an instant burst of energy from all the sugar in his breakfast. He walks quickly to school, runs around the playground full of energy, and talks to all his friends.
  • By the time Archie is getting settled in class to write a story he is feeling a little tired. His tummy is rumbling he is desperate for snack time.
  • He has used up all his energy as his breakfast did not contain complex carbohydrates.

Option 2 – Slow release food

  • For breakfast Archie eats a big bowl of porridge and has a glass of milk.
  • This breakfast is low in sugar and high in complex carbohydrate so its energy is released slowly over the morning.
  • By the time Archie is writing his story he still has energy and does not have a hungry tummy waiting for snack time.

Test your knowledge of food and energy with this short quiz.


  • Choose three foods you can find in your kitchen.
  • Imagine you were running a race.
  • Which out of the three foods would give you the most energy to run the race?
  • Remember you will need slow releasing energy to finish the race.

There's more to learn...

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Food as fuel group shot

Food as fuel