Canteen Manager Training Part 1

Nutrition Energy

Page last updated: 08 October 2013

Nutrition is the science of food and its relationship to health – how the human body uses food and processes the nutrients it contains to enable the body to perform functions (i.e. the heart to beat, the lungs to breathe, the kidneys to filter blood, the brain to think etc.).

Encompassed in this definition is how much energy (kilojoules) a body needs to maintain a healthy weight. Energy is delivered to the body through foods. Any energy consumed (in the form of carbohydrates, protein or fat) and not used for metabolism, growth or physical activity will be stored as body fat. There are many factors that dictate how much energy a person needs, but in simple terms the more the body moves, the greater the amount of energy will be needed.

The kilojoule is the measure of energy used in Australia. It is the International unit for energy, but some countries (e.g. USA) still use the calorie.

The conversion is: 4.2kJ = 1 calorie. We use it to determine how much energy a food will provide when we eat it.

The nutrients that provide energy are commonly referred to as macronutrients (carbohydrates, lipids, and proteins). Carbohydrates and proteins provide a similar amount of energy per gram of food. Lipids are a concentrated source of energy and provide almost twice the amount of energy than that supplied by proteins and carbohydrates.

For your information only:
CHOs = 16 kJ per gram of CHO
Protein = 17 kJ per gram of protein
Lipids = 37 kJ per gram of lipid

Children aged between 4-18 years require ~6500 to 14000 kJ per day. The approximate number of kilojoules a child consumes per day will depend on their age and physical activity level. The values given are for average physical activity only. For further information, please refer to the Nutrient Reference Values for Australia and New Zealand website.