To the authors’ knowledge, this paper is the first to explore the dietary regime provided in a total institution. Specifically, the aim of this study is to highlight gender differences in the dietary regimes of mental health patients. Using archival and documentary evidence, the study uses an unobtrusive research approach to explore the diets of mental health patients living in the Girifalco asylum, in southern Italy, during the second half of the 19th century. The evidence analyzed examines whether the dietary regimes that were rebuilt are perfectly in line with the principles of moral treatment. Concerning the study, limitations should be stated; although archival evidence suggests that the institutional meals provided in Girifalco asylum were nutritionally adequate (by gender), this is impossible to verify. In conclusion, the dietary regime provided at the Girifalco asylum was balanced both from a qualitative and quantitative point of view for healthy living in a total institution.