At the beginning of the 19th century, Colombian physicians thought of food as an essential factor in shaping human character and corporeality. Framed in a neo-Hippocratic system, health and racial differences were related not only to climate but also to the connection between food qualities and humoral fluids. For example, it was believed that the tendency to eat cold and moist food, as well as greasy substances, was one of the reasons why people in warm regions of Colombia were choleric, phlegmatic, and indolent. By midcentury, it was further argued that each regional type—a local racialized categorization based on geographic determinism—had certain diet habits and physiological characteristics that explained its character (sober, obedient, lazy, industrious, etc.), and that made this type “naturally” suitable for different kinds of work. During this period, the working population’s diet was not perceived to be a social problem requiring regulation, at least not by the government. In the midst of liberal reforms, the political elites were more focused on the economic and genetic integration (“whitening”) of highland Indians, and to a lesser extent blacks, than on producing a supposed “better race” through nourishment.But by the late 19th and the early 20th centuries, however, a new cultural framework that crossed the boundaries of thermodynamics, political economy, experimental physiology, and eugenics had begun to emerge in Colombia, converging in the social problem of nutrition. Centered on the analogy of the human body as a heat engine that transforms energy, local scientists began to conduct surveys of the eating habits of the “working classes,” analyses of the chemical and caloric composition of their foods, and studies on the metabolic characteristics of different regional populations. The results of these investigations were used to push the government to “restore the energies” of an impoverished population that was consistently thought to be weak and racially inferior, but capable of physiological and hereditable improvement. The cry of conservative elites for political and moral “regeneration” at the turn of the century also had a biological component—the optimization of the human motor. In the 1920s and 1930s, several campaigns and institutions were created for this social engineering, aimed at producing a modern, healthy, and industrious citizen. These campaigns gained special political force after the Liberal Party returned to power in 1930.