You need energy from calories for your body to work properly. Your body uses this energy to function properly.

To stay at around the same weight, the calories your body uses should be the same as the amount of calories you eat and drink.

If you do not use the same amount of calories as you eat and drink, your body weight may change. For example:

• You're likely to put on weight if you eat and drink more calories than you use. This is because your body stores the extra energy as fat
• You're likely to lose weight if you eat and drink fewer calories than you use. This is because your body uses its stored fat for energy