Kilojoules (also known as calories)
Energy is not a nutrient but is required by our body.
Foods provide our bodies with energy. We use this energy for physical activity as well as for basic functions like breathing, digestion, circulation and body temperature. Energy from food is measured in kilojoules (also referred to as calories or kilocalories). In NZ we refer to them as energy or kilojoules.
1 kcal = 4.184 kJ
Kilojoules affect body weight directly. If we consume more than we burn, our bodies will convert the excess kilojoules (energy) to fat and store it throughout the body. If we burn more kilojoules than we consume, our bodies will mobilise stored energy or “fat” to perform the basic functions and to fuel physical activities.
Energy / kilojoules come from four sources:
- Alcohol (not a nutrient because we do not need alcohol to survive)
|Carbohydrate||17kJ (4 kcal) per gram|
|Protein||17kJ (4 kcal) per gram|
|Fat||37kJ (9 kcal) per gram|
|Alcohol||29kJ (7 kcal) per gram|
As you can see, fat contains more than twice as much energy as carbohydrate and protein, closely followed by alcohol. This needs to be taken into account when we are watching our weight, or trying to reduce it.
The majority of our energy should come from carbohydrates, protein and good quality fat. Alcohol does not provide any nutrients but it is does contain energy.
Where should energy come from
Generally nutrition experts recommend that most people get energy from –
|45 – 55%||Carbohydrates||Wholegrain bread, breakfast porridge, rice, vegetables and fruit|
|12 – 15%||Protein||Fish, dairy, soy products, nuts, eggs|
|Less than 35%||Healthy Fats||Salmon, walnuts, canola and olive oil, avocados|
The amount of energy required varies for each person and can vary depending on age, size, gender and activity levels.
Factors that influence our need for energy from food
Below is a general guide only
*Sedentary – seated work with little or no strenuous leisure activity.
**Moderate – standing or walking work, or sedentary work with regular exercise of at least 30 minutes.
Age and kilojoules
Managing energy intakeMaintain calorie balance over time to achieve and sustain a healthy weight. People who are most successful at achieving and maintaining a healthy weight do so through continued attention to consuming only enough calories from foods and beverages to meet their needs and by being physically active.
Focus on consuming nutrient-dense (the amount of nutrients compared to the amount of energy) foods and beverages. For example alcohol and soft drinks are not nutrient, they have a lot of energy and low or no nutrients.
Nutrient-dense foods and beverages - vegetables, fruits, whole grains, fat-free or low-fat milk and milk products, seafood, lean meats and poultry, eggs, beans, peas and nuts.
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