Balancing Energy In and Out

What are kilojoules (kj) or Calories?

Energy is measured in kilojoules (kj) or Calories. So when we talk of 'energy in' we mean 'kilojoules in' (the kilojoules in food). Maintaining a healthy weight range it is important to help minimise the risk of many lifestyle diseases such as heart disease, some cancers and Type2 diabetes. The best way to maintain a healthy weight is to match the energy you consume from food with the energy that your body uses up.

On average, the amount of kilojoules required daily is:

Age	Male	Female
12-15 years	10 500 kj	9 000 kj
16-18 years	12 500 kj	9 500 kj
Adults up to 60 years	11 000 kj	9 000 kj
Over 60 years	9 000 kj	8 250 kj

Source: NHMRC, Canberra. These figures are only an average for the Australian population. The actual need for individuals will vary considerable depending on how active they are, their body build, state of health, age, weight and height.

Energy in = Energy out

To maintain body weight you need to aim to have 'energy in'. How much energy you need depends on how active you are each day, and whether or not your body is still growing (i.e. children and adolescents). The human body is designed for movement and activity - with a need for occasional, regular stops for refuelling and relaxation.

• 'ENERGY IN' comes from the food you eat. The protein, carbohydrate, and fat in the foods that you eat and drink provide energy. These nutrients deliver energy in varying amounts. Fat is the most concentrated source of energy, followed by protein and the carbohydrate. Alcohol also provides energy but is not really a food as it does not provide the body with any extra nutrients - instead it increases the amount of vitamins and minerals that the body needs.
• Carbohydrates - 16 kj per gram
• Protein - 17 kj per gram
• Fat - 37 kj per gram
• Alcohol - 27 kj per gram
• 'ENERGY OUT' depends on your age, stage of growth and development, and your usual activity level each day. So when we talk about 'energy out' we mean the amount of kilojoules you burn up staying alive (digestion, heart beat breathing etc.) and being active.

Energy Storage

What happens if you take in more energy than you need? The answer is simple - excess kilojoules will be stored as body fat.

The Best Energy Source

Your body prefers to use carbohydrate for energy to fuel your muscles and your brain. If there is not enough carbohydrate in the food that you eat, then your body will use fat for energy or as a last resort, protien. Fat and alcohol have almost twice the energy content of carbohydrate and protein - so it makes sense to go easy on them.