page_title: Wilbur Olin Atwater
section_title: Nutrition research and innovation
hierarchical_section_title: Wilbur Olin Atwater / Nutrition research and innovation
caption_attribution_description: English: Subject emerging from large respiration calorimeter from the Wilbur Olin Atwater Papers, Special Collections, USDA National Agricultural Library
context_page_description: Wilbur Olin Atwater was an American chemist known for his studies of human nutrition and metabolism, and is considered the father of modern nutrition research and education. He is credited with developing the Atwater system, which laid the groundwork for nutrition science in the United States and inspired modern Olympic nutrition.
  Atwater was director of the first United States Agricultural Experiment Station at Wesleyan University in Middletown, Connecticut and he was the U.S. Department of Agriculture's first chief of nutrition investigations.
context_section_description: Throughout his career, Atwater had been interested in human nutrition studies; having conducted the studies on behalf of the U.S. Fish Commission and the Smithsonian Institute, he had continued human nutrition research and the Storrs experiment station became known for nutritional studies.  Once the Storrs station was created, Atwater and his colleagues had begun conducting and publishing studies on the chemical compositions of food.  In 1891, he resigned as director of the Office of Experiment Stations in order to return to the Storrs and focus exclusively on nutrition research. After his resignation, Atwater was appointed special agent in charge of nutrition programs.  Through this position he organized extensive food analyses, dietary studies, experiments on the digestibility of food, investigations of energy requirements using human subjects, and studies of the cost and economics of food use and production. In 1894, Atwater received his first congressional appropriation, allocated to his laboratory for human nutrition research. Atwater's studies during this time were used to create dietary standards.  He based the standards off of average intakes, but did not regard them as quantitatively accurate; they logically varied based on age, sex, and activity level but he stressed that they were not metabolic studies.
  He went on to conduct metabolic studies related to the dietary standards, based on observations from  his work with Voit, who had used a Rubner respiration calorimeter to conduct similar experiments on small animals.  Together with Charles Ford Langworthy, they compiled a digest of close to 3,600 metabolic experiments as a primer to the research they would conduct. Atwater went on to work with Physicist Edward Bennett Rosa and Nutritionist Francis Gano Benedict to design the first direct calorimeter large enough to accommodate human subjects for a period of days.   The calorimeter, or human respiration apparatus, was built to precisely measure the energy provided by food. Atwater wanted to use it to study and compare the nutrient contents of different foods and how the human body consumes those nutrients under various conditions of rest and work.   The calorimeter measured human metabolism by analyzing the heat produced by a person performing certain physical activities; in 1896 they began the first of what would accumulate into close to 500 experiments. Through their experiments, they were able to create a system - which became known as the Atwater system, to measure the energy in units, known as food calories. With the machine, the dynamics of metabolism could be quantified and the relationship between food intake and energy output could be measured. "The experiments are made with a man inside a cabinet, or a respiration chamber, as it is called. It is in fact a box of copper incased [sic] in walls of zinc and wood. In this chamber he lives—eats, drinks, works, rests, and sleeps. There is a constant supply of fresh air for ventilation. The temperature is kept at the point most agreeable to the occupant. Within the chamber are a small folding cot-bed, a chair, and a table. In the daytime the bed is folded and laid aside, so as to leave room for the man to sit at the table or to walk to and fro. His promenade, however, is limited, the chamber being 7 feet long, 4 feet wide, and 6 feet high. Food and drink are passed into the chamber through an aperture which serves also for the removal of the solid and liquid excretory products, and the passing in and out of toilet materials, books, and other things required for comfort and convenience." His research was informed by the first law of thermodynamics, taking into account that energy can be transformed but it cannot be created or destroyed, despite the belief at the time that the law only applied to animals because humans were unique.  Earlier experiments concerning calorie intake and expenditure had proven that the first law applied to animals and Atwater's findings demonstrated the law applied to humans as well. Through the experiments he demonstrated that whatev
caption: Subject exits respirator calorimeter in Atwater's laboratory. Courtesy of Special Collections, U.S. National Agricultural Library
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