Therapeutic translations of the microbiome-gut-brain (MGB) axis are reconstructing the educational subject in a manner amenable to Foucauldian analysis. Yet, at the same time, under the sway of MGB research social scientists are taking a biosocial turn that threatens the integrity of Foucault's historicizing philosophical project. Meeting that challenge head-on, this article argues that the MGB axis augments the neurobiological constitution of the educational subject by means of a dietetic mode of subjectivation. Absent a pedagogical element, there is a hollowness to critical academics' claims that holobiontic self-conceptions springing from the axis can elicit a resistant subjectivity. Though wild pedagogies might inform a resistant tactics of the self, contemporary self-technologies are -- as Foucault has taught us -- a pale shadow of the ancient Greek conception of dietetics as an holistic, embodied and ensouled practice. At the intersection between the disciplinary apparatuses of criminology and education, therefore, the MGB-driven biosocial turn unambiguously reinforces the social control function of schooling.