This article analyses the manner in which the physical and sexual energy of the white, native South American and black populations was represented in reading books for elementary school children in Spain and Colombia between 1900 and 1960. Ninety reading books from representative authors were examined. It was found that the ideal of extraordinary physical vigour attributed to the white male was decisive in justifying Spanish imperialism, the superiority of the male in the patriarchal family and the intervention of authorities in administering people's bodies. In the case of Spanish texts, the might attributed to the white race was shown as having a motive of pride, whereas in the Colombian case, the mixture with Native Americans and blacks tended to be used as an explanation for the "weakness" of Colombians. Evidence is also found of the way in which education was implicitly conceived as a process of cultural "whitening".