Background: Obesity-related metabolic dysfunction includes adipose inflammation, hepatic steatosis, insulin resistance, dyslipidemia, and intestinal disturbances. Avenanthramides are oat-specific phenolic amides, and their contribution to metabolic responses to oat foods is difficult to attribute because beta-glucan and the wider oat matrix can affect the same endpoints. This narrative review examines their mechanisms, exposure biology, evidence attribution, and translational readiness. Methods: Cell, animal, pharmacokinetic, and human studies were organized by chemical definition and intervention format, including purified congeners, characterized foods, enriched matrices, and whole-oat products. Parent compounds, circulating metabolites, target tissues, and clinical outcomes were interpreted separately. Results: In cell and animal models, avenanthramides influence NF-κB-related inflammation, redox regulation, hepatic insulin signaling, glucose production, fatty-acid metabolism, and intestinal ecology. Human studies demonstrate dietary exposure to parent compounds and metabolites, while clinical evidence comes mainly from small enriched-food exercise studies. Among the studies identified and appraised in this narrative review, none established an avenanthramide-specific effect on adiposity, liver fat, insulin sensitivity, dyslipidemia, or other cardiometabolic outcomes. Conclusions: The current literature supports measurable exposure and candidate mechanisms; a validated anti-obesity effect requires targeted clinical trials. Next studies need stable, analytically defined preparations, metabolite-informed dose selection, matched food controls, and trials that link measured exposure with prespecified clinical outcomes.