What is energy made of?
Scientists measure energy in tiny units called ‘joules’. A joule is the amount of energy used to move an object one metre in one second. We can understand this more easily by knowing it is about the amount of energy we need to lift an apple one metre into the air.
How much energy do we need?
People need different amounts of energy, depending on age, size, and activity levels.
We need extra energy to:
How do we get energy?
We get energy from the food that we eat. Food is broken down in the digestive system and nutrients travel to where they are needed in the blood. We get most of our energy from carbohydrates, protein, and fat.
Our body uses most of the energy we get just to stay alive! 40 to 70 percent of the energy we take in (depending on our age and size) is needed to keep our bodies working; so that our hearts beat, we keep breathing, and we can digest food to keep giving us energy. This is called our 'Basal Metabolic Rate’.
‘Dietary Thermogenesis’ is the energy we use to digest food, and transport and store nutrients for later use. This takes about 10 percent of our energy, every day.
We also need energy from food to move and be active. Physical activity can use between 20 and 50 percent of our energy every day, depending on how active we are.
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