IN SUPER SIZE ME, his 2004 documentary on the fast-food industry, Morgan Spurlock asks Americans if they know what a calorie is. A few shake their heads, but most gamely guess that it has something to do with fat. 'It's on the side of the cereal box', one explains. 'Calories are not good', another knows for sure. Even a specialist had difficulty recalling that a calorie is a measure of the energy content of food, an amount sufficient to raise the temperature of one litre of water one degree.
In the first half of the twentieth century, figures of all kinds, from gross national products to birth rates, became the language of state-craft, yet the original meaning of the numbers melted away, leaving behind distinctive patterns on thought and policy. The calorie is one such measure. Its initial purpose was to inventory the food supplies and appetites of whole populations, but it grew instead into a measure of individual self-control. Along the way it altered the logic of international affairs, placing food at the centre of trade controversies, humanitarian crises, and development schemes.
Europeans first measured food in calories in 1883, but Americans devised the instruments that made the calorie a practical, everyday measurement, and it was in the United States that the calorie left its most visible imprint on foreign policy. It popularized a set of assumptions that allowed Americans to see food as an instrument of power, and to envisage a 'world food problem' amenable to political and scientific intervention.
The work of rendering food into hard figures began after breakfast on March 23rd, 1896, when Wilbur O. Atwater (1844-1907) sealed a student into an airtight chamber in the basement of Judd Hall on the Wesleyan University campus where Atwater was Professor of Chemistry. The apparatus was described by the press as resembling a meat locker, a room 'about as large as an ordinary convict's cell' lined with copper and zinc, its interior visible through a triple-paned glass aperture. Its occupant, A. W. Smith, took measured quantities of bread, baked beans, Hamburg steak, milk, and mashed potatoes through an airlock during rest periods which alternated with intervals of weightlifting. Thermometers, hygrometers and electric condensers, pumps, and fans precisely measured the exchange of heat, air and matter into and out of the chamber. Smith was inside a calorimeter, a device previously used to measure the combustive efficiency of explosives and engines.
The national press found a Chekhovian parable in the voluntary captivity of Smith, alternately described as 'the man in the box' and 'the prisoner of science'. On the second day, Atwater had to turn away a young New York woman who appeared at the lab asking to be allowed into the chamber, but despite distractions the calorimeter's first run was an enormous success, generating pages of calculations and a $10,000 Congressional appropriation to continue the work. Atwater invited champion cyclist Nat Butler to establish 'how far a man ought to ride a bicycle on one egg'. Wesleyan's football captain volunteered to take his French final inside the device to determine the quantum of heat generated by an hour of cogitation. But it was the statistical results--tables that assigned calorie counts to specific foods and tasks--that made Atwater a household name. Clergymen applauded the discovery that the body created in the divine image produced energy more efficiently than a locomotive. The Women's Christian Temperance Union campaigned against Atwater after an experiment in which a test subject subsisted for six days on a diet 'largely composed of alcohol' confirming that liquor was a food. But most sensational of all was Atwater's pronouncement that mathematical laws governed the ordinary act of eating.
The calorimeter had ramifications for the management of factories, prisons and schools, as well as the provisioning of armies. It could reduce the cost of rations, and test their suitability for the tropics and for varying conditions of work. …