Based on a comparative study of Euro-American and South Korean college students’ cultural models of the ideal male body, I show that Euro-Americans and Koreans conceptualize fat in distinct ways related to each group’s cultural model of acceptable personhood. Drawing on cultural models theory and using cultural domain analysis and residual agreement analysis, I demonstrate that while Euro-Americans tend to view fat as a black-and-white moral issue through the perspective of “healthism,” Koreans understand fat to be a negative appearance trait within the more flexible, if discriminatory, lens of “lookism.” Because healthism invites mutually reinforcing moral and medical judgments of fat individuals, fatness becomes an index of aesthetic undesirability, compromised character, and danger, leading to fat stigma. On the other hand, the lens of “lookism” deems fatness as one of many potential physical flaws that can be corrected by dietary or surgical intervention and mitigated through self-maintenance practices. Therefore, under “lookism,” fatness invites negativity, but it does not index poor character except in the context of other undesirable traits. As a result, the concept of fat stigma may not adequately explain the treatment of fat in the Korean context.