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The kilojoule is the unit now most widely used for expressing food energy. It is based on
an
international system of units designed to minimise differences in terminology between
countries.
Energy used to be measured in kilocalories (sometimes this was simply called calories). One
kilocalorie is equivalent to 4.186 kilojoules. As an approximation, to find the number of
kilojoules
in food, multiply the number of kilocalories by four.
The energy (kilojoules) provided by a food depends on the amount of protein,
carbohydrate, fat,
alcohol, water, and dietary fibre in it. The energy contributed by these food components is
shown
in the following table:
| FOOD COMPONENT | KILOJOULES
PER GRAM |
KILOCALORIES
PER GRAM |
| Protein
Carbohydrate Fat Alcohol Water Dietary fibre (if fermented in the large intestine) |
17
16 37 29 0 13 |
4
4 9 7 0 3 |
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