What is Energy?

Energy is another word for kilojoules (or calories). When we eat, our bodies transform the energy stored in food into energy to keep our bodies working - it keeps cells intact, it repairs damage, it drives movement, it enables processes like seeing, hearing, thinking and tasting.

People do not eat pure energy - they eat nutrients in the form of food. Then these nutrients are used by the body to provide energy. So just as a car burns petrol to run, our bodies burn energy or fuel to supply energy to operate. We fuel our body by eating and drinking. However, some foods provide better quality fuel than others.

The three main nutrients from food that supply the body with energy - carbohydrate, fat and protein - are all found in dairy foods.

Carbohydrate, fat and protein are 'burnt' (or oxidized) to provide the body with fuel. This means they are combined with oxygen in specific biochemical reactions. Overall, these reactions are called metabolism.

Energy facts:

  • Fat, protein and carbohydrate in foods all provide energy, but in different amounts.
  • Carbohydrates are the body's preferred source of fuel. Carbohydrate is broken down into simple sugars such as glucose during the digestion process and then used to provide energy to the brain and by all the other cells of the body.
  • A small amount of glucose is stored in the muscles and other places in the body in the form of glycogen. When needed, this small amount of stored glucose can very quickly be used to produce energy.
  • The other main store of fuel in the body is fat, which can be released for fuel. However, fat takes a little longer to produce the energy that we need to be active and healthy.
  • Energy sources, such as glucose, are transported around the body by the blood. Blood also transports oxygen (needed to 'burn' the fuel), and nutrients (to ensure the burning is controlled). Every cell in the body produces energy for fuel.
  • Vitamins and minerals are important for the biochemical reactions in the body that produce energy. They also help blood cells to deliver oxygen around the body. Some of the nutrients that help us use energy include riboflavin, phosphorous and vitamin B12 which are found in dairy foods.

Now go to Students' Energy Needs.