Your body changes the chemical energy contained within the food you eat into the energy you need to stay alive.
Different foods contain different amounts of energy. For example, a typical meal of a hamburger, chips and a fizzy drink contains about 4000 kJ of energy.
The hamburger contains approximately 2000 kJ, the chips contain 1300 kJ and the fizzy drink contains about 700 kJ of energy.
This may seem like a lot of energy, but different people have different energy needs depending on their age and lifestyle. Shown below are the approximate energy needs of a wide range of people.
|Person||Energy need per day (kJ)|
|2 year old||4000|
|10 year old||8000|
|14 year old girl||10000|
|14 year old boy||12000|
|Adult male with an active job||14000|
The energy needs depend on age and lifestyle. An active person requires more energy than a person who works at a computer most of the day.
It is important to provide your body with the correct amount of energy.
If a person takes in a lot of energy but does not lead an active lifestyle then they may become overweight, but a person who does not take in enough energy may become underweight, both of which can cause health issues.
It is also important to have a balanced diet, containing the correct amounts of vitamins and minerals.