Prior to the identification of the micronutrients we call vitamins in the 1930s, nutrition science was mainly a science of animal energetics, or the study of how animals metabolize food into energy. Animal energetics, in turn, was a science of animal starvation. It was also a science of race.
Cover for Josh Berson's book "The Meat Question"This article is adapted from Josh Berson's book “The Meat Question: Animals, Humans, and the Deep History of Food.”
The questions physiologists asked about animal energetics were straightforward: How much energy was required to keep an animal from starving under various conditions (for example, physical regimen, ambient temperature)? How much protein — specifically, in the early days, how much meat — was required to maintain the animal in nitrogen equilibrium, that is, to ensure that the quantity of nitrogen lost as urea in the urine was equal to that ingested? Efforts to measure metabolic rate by gauging the volume of carbon dioxide expelled in respiration went back at least to the French chemist Antoine Lavoisier's experiments with guinea pigs in the 1780s, but for a long time, respirometry remained cumbersome and subject to the concern that what an animal did under a respirometer hood did not represent a good approximation to what it did out in the world. So in most labs, the key methods of research into the 1910s were collecting animal waste and fasting animals, often to the death.
