The Public Health Nutrition (PHN) community categorizes dietary-related chronic illnesses as “noncommunicable,” fixing these afflictions within individual bodies where they are best managed by individual choices. Yet within clinical encounters in Guatemala, nutritionists and patients treat eating and dieting as relational, transmissible practices. Patients actively seek nutritionists’ care, asserting their self-care attempts have failed and they need support from others; nutritionists meanwhile develop treatment plans that situate “personal choice” as lying outside the control of a solitary individual. This article moves between international policy–pedagogy and patient–nutritionist interactions to examine forms of personhood, responsibility, and rationalities of choice present in body weight–management practices in Guatemala. Although nutrition discourses might appear to exemplify how institutional (bio)power manifests through internalized self-monitoring and preoccupation for one’s own self, I argue that within the lived experiences of “nutrition-in-action,” the self–body of the patient becomes broadly conceived to include the nutritionist, the family, and the broader community.