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Energy requirement corresponds to the amount of energy needed to maintain the basal metabolism and to support daily physical and mental activities.
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Basal metabolism is the energy expended by the body at complete rest to maintain its vital functions.
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Nutrition needs correspond to the minimum daily quantities of each nutrient required to maintain a person in good health.
The human body's nutrient and energy requirements vary according to a number of factors, including age, sex, weight, height, level of physical activity and individual metabolism.
The energy value of a nutrient corresponds to the amount of energy it can supply to the body when consumed. This energy is generally expressed in kilocalories (kcal), also known as large calories (Cal), or kilojoules (kJ).
In nutrition, the kilocalorie (kcal) is generally used as the unit of measurement, because the calorie (cal) is too small to quantify the energy stored in food.
In popular language, the kilocalorie is also called the large calorie and its abbreviation can also be written: Cal (with a capital C). The large calorie (Cal) is also used on nutrition labels in Canada. Be careful not to confuse the units.
The energy value of a food depends on the nutrients it contains. The three nutrients that provide the body with energy are carbohydrates, lipids (fats) and proteins.
|
Nutrient |
Carbohydrates |
Lipids (fats) |
Proteins |
|---|---|---|---|
|
Energy value (kcal/g or Cal/g) |
4.0 |
9.0 |
4.0 |
|
Energy value (kJ/g) |
17.0 |
37.0 |
17.0 |
A 100 g serving of broccoli contains approximately 1.1 g of carbohydrates, 0.78 g of lipids and 2.1 g of proteins.
To calculate the total energy value of this amount of broccoli in kilojoules, the mass of each nutrient must first be multiplied by its energy value.
|
Nutrient |
Mass |
Energy value |
Energy value |
|---|---|---|---|
|
Carbohydrates |
1.10 | 17.0 | 18.7 |
|
Lipids (fats) |
0.78 |
37.0 |
28.9 |
|
Proteins |
2.10 |
17.0 |
35.7 |
|
Total |
83.3 |
||
Then, the energy values of all the nutrients can be added to obtain the total energy value of 100 g of broccoli: 83.3 kJ.
The nutrition facts of a food is a description of its nutrients. It is generally presented in a table on the nutrition label.
The nutrition label is a label indicating, among other things, the energy and nutrition values of one serving of food. It is found on most packaged food products and helps consumers make more informed food choices. The following example shows the different types of information that can be found on a nutrition label.
The nutrition facts for one serving of almond milk are shown on the nutrition label.
The percentage (%) of the daily value of protein is not shown on the nutrition label, because the average daily amount consumed by Canadians far exceeds the minimum required value.
Cholesterol and sodium are prominently displayed on the nutrition label, because excessive consumption of these nutrients is associated with high risks of obesity, heart disease and hypertension. For these reasons, it is recommended to choose foods that are low in sodium and cholesterol.