Daily Archives: March 10, 2012


Dr. Wilbur Atwater, Calorie Expert

There aren’t many words in the English language that end with I-E.  There’s brownie, movie, eerie, zombie, prairie, wedgie, genie, bookie… OK, so there are more than I thought.

What I had previously believed to be a rare example of a word ending in I-E is calorie.  It entered the language in the 19th centurie (sorry, century) thanks to a French scientist named Nicolas Clément.  He defined it as a unit of heat, and derived “calorie” from the Latin word calor, which means… right, heat.

Clément’s calorie was the amount of energy needed to increase the temperature of water by 1° centigrade.  That kind of calorie (a.k.a. the small calorie) still has some scientific applications, but the kind we have all learned to dread is actually a kilogram calorie — 1,000 small calories.  To avoid confusion, the food-energy calorie is often capitalized, which I’ll start doing now.

The Calorie (a.k.a. the large calorie, or in Europe the kcal) was popularized, if that’s the right word, by an American professor of chemistry at Wesleyan University in Connecticut.  At the end of the 19th century, Wilbur Atwater invented a device he called the respiration calorimeter, a chamber he used in experiments to basically measure the balance between food intake and energy output of his test subjects.

Atwater and his colleagues gave the subjects precisely measured portions of food.  Then the subjects, students who stayed in the little chamber for days at a time, would ride a stationary bicycle or perform other tasks.  The calorimeter evaluated the heat that the subjects generated.  The energy needed to increase one kilogram of water by 1° centigrade came to be known as a Calorie, thanks to articles Wilbur Atwater wrote for national publications in the U.S.  The general populace caught on to the notion that all kinds of foods had nutritional values that could be expressed by numbers.

Atwater got himself in hot water, so to speak, with temperance groups because he felt duty-bound to report his finding that alcohol had some nutritional value.  That fact was soon included in the advertising of companies that made liquor. 

Professor Atwater died in 1907, but his pioneering work was carried on by a Wesleyan co-researcher named Francis Benedict.  The book Eating History: 30 Turning Points in the Making of American Cuisine, written by Andrew F. Smith, mentions one of Benedict’s proudest achievements.

He developed a calorimeter, the book says, “large enough to hold twelve Girl Scouts for an extended period of time.”

I had no idea that Girl Scouts of long ago had a role in establishing the Calorie as a scientific unit, but I’ve been aware that their Girl Scout cookies had a role in the extra calories I’m wearing around my waist.  Oh, yeah… and come to think of it, cookie is another I-E word.