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Does the history of food energy units suggest a solution to "Calorie confusion"?

Overview of attention for article published in Nutrition Journal, December 2007
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About this Attention Score

  • In the top 5% of all research outputs scored by Altmetric
  • High Attention Score compared to outputs of the same age (95th percentile)
  • Good Attention Score compared to outputs of the same age and source (69th percentile)

Mentioned by

2 news outlets
8 tweeters
1 Facebook page
4 Wikipedia pages
1 Q&A thread
1 video uploader


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Readers on

40 Mendeley
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Does the history of food energy units suggest a solution to "Calorie confusion"?
Published in
Nutrition Journal, December 2007
DOI 10.1186/1475-2891-6-44
Pubmed ID

James L Hargrove


The Calorie (kcal) of present U.S. food labels is similar to the original French definition of 1825. The original published source (now available on the internet) defined the Calorie as the quantity of heat needed to raise the temperature of 1 kg of water from 0 to 1 degrees C. The Calorie originated in studies concerning fuel efficiency for the steam engine and had entered dictionaries by 1840. It was the only energy unit in English dictionaries available to W.O. Atwater in 1887 for his popular articles on food and tables of food composition. Therefore, the Calorie became the preferred unit of potential energy in nutrition science and dietetics, but was displaced when the joule, g-calorie and kcal were introduced. This article will explain the context in which Nicolas Clément-Desormes defined the original Calorie and the depth of his collaboration with Sadi Carnot. It will review the history of other energy units and show how the original Calorie was usurped during the period of international standardization. As a result, no form of the Calorie is recognized as an SI unit. It is untenable to continue to use the same word for different thermal units (g-calorie and kg-calorie) and to use different words for the same unit (Calorie and kcal). The only valid use of the Calorie is in common speech and public nutrition education. To avoid ongoing confusion, scientists should complete the transition to the joule and cease using kcal in any context.

Twitter Demographics

The data shown below were collected from the profiles of 8 tweeters who shared this research output. Click here to find out more about how the information was compiled.

Mendeley readers

The data shown below were compiled from readership statistics for 40 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
Denmark 2 5%
Unknown 38 95%

Demographic breakdown

Readers by professional status Count As %
Student > Master 9 23%
Student > Bachelor 9 23%
Researcher 6 15%
Student > Postgraduate 4 10%
Student > Ph. D. Student 4 10%
Other 6 15%
Unknown 2 5%
Readers by discipline Count As %
Medicine and Dentistry 12 30%
Nursing and Health Professions 6 15%
Agricultural and Biological Sciences 6 15%
Biochemistry, Genetics and Molecular Biology 3 8%
Arts and Humanities 2 5%
Other 9 23%
Unknown 2 5%

Attention Score in Context

This research output has an Altmetric Attention Score of 31. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 04 September 2020.
All research outputs
of 15,923,161 outputs
Outputs from Nutrition Journal
of 1,217 outputs
Outputs of similar age
of 307,857 outputs
Outputs of similar age from Nutrition Journal
of 118 outputs
Altmetric has tracked 15,923,161 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 95th percentile: it's in the top 5% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 1,217 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 29.6. This one has done well, scoring higher than 81% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 307,857 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 95% of its contemporaries.
We're also able to compare this research output to 118 others from the same source and published within six weeks on either side of this one. This one has gotten more attention than average, scoring higher than 69% of its contemporaries.