This paper challenges the static view of marginalized identities by adopting a dynamic perspective, focusing on the subjective nature of obesity. Specifically, we utilize the context of subjective body fatness to explore within-individual fluctuations in stigmatized views by employees over time. We examine if how someone feels ‘right now’ may exhibit unique and stronger effects on one's job than how big they feel in general. Drawing from stigma theory, we utilize an experience sampling design to consider how weekly variations in subjective body fatness influence self-devaluation and, subsequently, task performance among customer service workers over a period of five weeks. The results reveal that weekly subjective body fatness uniquely relates to subsequent self-devaluation, supporting a dynamic, within-person nature of stigmatization. Furthermore, self-devaluation mediates the relationship between subjective body fatness and subsequent task performance. Thus, marginalized identities are not just a category that one is in, but they are a dynamic identity that can change across time. Overall, this study sheds light on the nuanced interplay between self-perception and the ever-changing dynamics of marginalized identities, particularly in the context of obesity.