Energy is amazing. You can't see it, touch it, smell it or hear it, yet it is used everyday by many things. Energy comes from different places. The source of energy for a car is petrol, for a computer it's electricity and for our bodies it’s food and drink.
Energy and the body: What you eat and drink gives your body the energy it needs for the important processes of life, like breathing or growing. But it also gives us energy for activities like walking, running or just talking. You use energy all the time. The more active you are, the more energy you use.
Your body needs energy to:
Your body uses more energy when you are active, and less if resting. It even uses energy when you’re asleep. When you exercise or play games, the heart, muscles and lungs have to work harder. Next time you're running or walking, think about what happens to your heart rate, breathing and temperature.
Different people need different amounts of energy, depending on their age, gender, size, health and how active they are.
Some people live busy, active lives, exercise a lot and are rarely still except when asleep. These people use a lot of energy so they need to eat more food to give them that energy.
Other people are less active, preferring to read or watch TV. They need less food because they use less energy.