What is energy?
The term 'energy' refers to the amount of kilojoules found in the product. It is this energy the body uses as a fuel source to function properly.
Every thing you need to know
Energy is the term used when referring to the kilojoule content of food and drink (as seen in a nutrition information panel or front-of-pack %DI labels),
How is energy measured?
'Kilojoule' (kJ) is the measurement unit used when referring to the amount of energy a food or drink contains. The term kilocalories (kcal) (often shortened to Calories) is the older imperial measurement that is used in many parts of the world such as the US and the European Union.. Many people in Australia who grew up with this term also still use it. One kilocalorie is equal to 4.18 kilojoules, so to convert kilojoules to kilocalories, simply divide the kilojoule figure by 4.18.
The kilojoule content of foods depends on the amount of carbohydrate, fat, protein and alcohol present. Fat contains the highest amount of kilojoules per gram, followed by alcohol, carbohydrate and protein*:
Fat = 37kJ per gram
Alcohol = 29kJ per gram
Carbohydrate = 17kJ per gram
Protein = 17kJ per gram
To reduce kilojoule content, it is often recommended that people reduce their fat and carbohydrate intake, including their intake of total sugar.
How do you use energy from food and drinks?
When you eat, the process of digestion converts the energy from foods to another form that the body can use to perform its various functions. Any unused energy is stored, mainly as body fat, for later use. As well as containing kilojoules, foods also contain important vitamins and minerals that help release the energy from food and perform other vital functions in the body.
What are your kilojoule requirements?
The total amount of kilojoules needed by the body each day varies depending on your age, gender, body composition and activity levels. Pregnancy, lactation, growth and illness can all increase your kilojoule requirements. There are reference daily intakes for kilojoules for people of all ages, however as a general guide, an average adult's kilojoule requirements are 8700kJ per day. The average adult's kilojoule requirement of 8700kJ is what our %DI labels are based on.
Why is it important to know your kilojoule requirements?
All living creatures need energy (kilojoules) from foods and drinks to maintain life. The human body uses energy to maintain basic functions such as breathing, heart function and maintaining body temperature (known as the body's resting metabolism). Energy is also needed to support voluntary actions such as movement and exercise. Once the body receives enough kilojoules to perform its daily functions, any excess kilojoules (from consuming too much food and drinks) is stored as fat. It is therefore important to maintain energy balance in the body where the amount of kilojoules taken in is equal to the amount of kilojoules used up. Having excess kilojoule intake over time can lead to weight gain, while having too few kilojoules can lead weight loss.
Maintaining a healthy weight
Including a variety of foods such as fruits and vegetables, wholegrain breads and cereals, lean meats or alternatives, low-fat dairy products and heart-healthy fats each day is essential to meet the body's nutrient requirements. Making sensible, balanced choices within these key food groups, while not exceeding daily kilojoule requirements, and including adequate fluid and appropriate levels of physical activity every day, can help to achieve a healthy weight and a balanced and healthy lifestyle.
Keeping track of kilojoules
Unless you carry a pocket kilojoule counter book around with you, it can be hard to keep track of your daily kilojoule intake! Food labels in Australia are required to list the kilojoule content of a food or drink in 100 grams or 100 ml and also for one serving of the food in the product's nutrition information panel., Most fresh and unpackaged foods do not carry this information. As a general guide, here is the kilojoule content of common foods*:
|Vegetables||½ cup vegetables, or 1 cup salad, or 1 small potato||75-250 kilojoules|
|Fruit||1 medium piece ( e.g. apple, orange ) or 2 smaller pieces ( e.g. apricot )||300 kilojoules|
|Breads and cereals||2 slices of bread, or 1cup of cooked rice or pasta||600 kilojoules|
|Dairy||1 cup of milk, or 1 small (200g) tub of yoghurt, or 40g (2 slices) of low fat cheese, 1 cup of soy milk||375-730 kilojoules|
|Meat||1/2 cup lean mince, 2 small chops, 100g cooked fish fillets, 2 small eggs||600-850 kilojoules|
|Drinks||1 glass ( 250 mL ) of water or fruit juice||0-450 kilojoules|
Kilojoules burnt in activity
The other side of the energy equation is energy expended through physical activity. Overall, to maintain energy balance in the body, keep active every day, make food and drink choices to help you meet your daily nutritional needs, and watch your portion sizes!
Stay tuned for more information, tips and tools to help you.
*The Australian Guide to Healthy Eating - Background information for nutrition educators. Commonwealth of Australia 1998.