Abstract

This article examines how digital self-tracking practices (DSTPs) reconfigure the individualistic ethos of healthism through a posthumanist onto-epistemological shift. Healthism, originally formulated by Robert Crawford in 1980, refers to an ideology that prioritises individual health as the foundation of well-being, promoting self-management through lifestyle choices and placing responsibility on individuals. Based on 23 interviews with users of insulin pumps and fitness applications in Chile, this study employs a critical thematic analysis informed by Science and Technology Studies. Findings show that DSTPs reproduce and transform the logic of healthism, reinforcing responsibility while reshaping the conditions under which health is known and managed. Insulin pumps embed users in tightly regulated medical regimes, whereas fitness applications foster gamified self-optimisation and promote competition. Both technologies intensify the individualistic ethos while displacing introspection with data-driven knowledge. This highlights a crucial paradox: DSTPs legitimise themselves through discourses that deny the very power of discourse, elevating numbers as the only credible source of truth. Thus, the digital subject is caught between the demand to ‘know thyself’ and the recognition that such knowledge depends on technologies that both empower and constrain it. © 2025 The Author(s). Sociology of Health & Illness published by John Wiley & Sons Ltd on behalf of Foundation for the Sociology of Health & Illness.