This paper examines the link between lipophobia and representations and experiences of obesity in Catalonia (Spain) from two points of view: that of the physicians and other health professionals who diagnose and treat obesity as an illness, and that of their patients, especially those between adolescence and early adulthood. The qualitative data demonstrate that the increasing social rejection of fat people can be traced not only to moralizing discourses on “excessive” food consumption or the commodification of slenderness and health, but also to the recent definition of obesity as a disease. The medicalization of fatness, far from helping to destigmatize obesity, is becoming a way of resignifying it in moral terms. While doctors’ and patients’ perspectives diverge in some ways, they converge in others. In this text, I focus on the points of convergence arguing that biomedical understandings of obesity and overweight are characterized by a profound ambivalence. Young patients are regarded both as innocent victims of a permissive consumer society, and guilty of not following doctors’ orders. Although the family is held accountable for overweight or obesity in children, as young people become more independent, guilt is individualized and environmental causes are limited to inappropriate diet and insufficient exercise. Most narratives of young people with weight problems reflect similar ideas about the causes and the responsibility for obesity. Their acceptance of the basic premise that deviating from weight standards and rules for healthy eating are voluntary actions leads them to lose faith in themselves. The stigmatization of obesity thus becomes a vicious circle: the obese acceptance—even consider normal—the incriminations leveled at them, and blame themselves for their situation and their inability to prevent it.