On 2009/01/31, at 3:37 PM, David wrote:
How long after the initial metrication would it take for food
companies to start using "joules/kilojoules" instead of
"calories?" (They would use kilojoules and not just joules,
correct?) Even if people don't use centimeters or kilograms in their
daily lives they've at least heard of them. But I don't think anyone
outside of the scientific community has heard of the "joule."
So would calories stay or would those be changed as well? Do they
use joules/kilojoules on food packages in metric countries?
Dear David,
In Australia, people who package foods are legally required to use
kilojoules for the energy content of the food. Further, they are
required to give a figure in kilojoules for a normal serving and for
100 grams of the food.
Food nutrients have to be listed in a Nutrition Information Panel. The
NIP provides information on seven nutrients: energy (kilojoules),
protein, total fat, saturated fat, total carbohydrates, sugars and
sodium. Cholesterol content does not have to be listed unless a claim
is made. You can get full information, for the state of Victoria,
which is typical, from http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Food_labels_explained?OpenDocument
There are two main problems with calories, Calories, gram-calories,
kilogram-calories, kilocalories, and kiloCalories etc. The first is
that these words are not supported internationally so that individual
companies might use different spellings for reasons best known to
themselves. From the six examples that I have given here a kiloCalorie
is a million times larger than a calorie because of the spelling. A
second problem is that calories vary from one temperature to another.
A 20 °C calorie is not the same as a 38 °C calorie for example. This
problem with temperatures and calorie measurements has been known
since the 1860s or 1870s when the British Association for the
Advancement of Science decided to throw out all of the different
calories in favor of the joule that is always the same; the joule has
been the internatioally accepted unit for all forms of energy since
1899. A joule is not much energy — you use a joule of energy when you
pick up a medium sized apple (1 newton) and place it on a shelf (1
metre high) — so it is usual to talk about kilojoules of energy, or
megajoules, or gigajoules, …
By the way, the word, calorie, became popular in the USA after 1919
when Dr Lulu Hunt-Peters wrote a book about the calorie content of
food. Leaving aside the issue of the garbled quantity (food energy)
with the measuring word, calorie, Dr Hunt-Peters defined a calorie as
the amount of heat needed to heat 4 pounds of water by 1 degree
Fahrenheit. Sometime during the last 90 years someone changed the
spelling of Dr Hunt-Peter's calorie to Calorie (a Calorie is 1000
times larger than a calorie).
With respect to timing, i.e. your question, 'How long does it take?'
this depends on how your government reacts to your nutritionists who
will fight tooth and nail to keep their old calorie words, even when
they know about their unreliability, because they have built up a
strong mindset that revolves around a set of conversion factors. They
have memorised things like 'how many calories there are in a slice of
bread' and 'how many calories an active woman needs each day' and they
are loath to give up these habits. In Australia, it took about 30
years for the dust to settle (1970 to 2000) but there are still some
out-liers. The success here was, I believe due to the fact that all
foods were labelled as I mentioned previously and the nutritionists
simply got worn down by the constant questions along the lines of:
'you told me to eat xxx calories of bread but the packet is in
kilojoules, how do I know what to do?'
Cheers,
Pat Naughtin
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has
helped thousands of people and hundreds of companies upgrade to the
modern metric system smoothly, quickly, and so economically that they
now save thousands each year when buying, processing, or selling for
their businesses. Pat provides services and resources for many
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and government metrication leaders in Asia, Europe, and in the USA.
Pat's clients include the Australian Government, Google, NASA, NIST,
and the metric associations of Canada, the UK, and the USA. See http://www.metricationmatters.com
for more metrication information, contact Pat at [email protected]
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