The sources collectively explore the significant impact of intramuscular fat, or marbling, on the quality of grilled steaks. They explain how marbling enhances flavor through the release and creation of aromatic compounds when heated, improves tenderness by physically disrupting muscle fibers and providing lubrication, and contributes to perceived juiciness by adding melted fat and a rich mouthfeel. Factors influencing marbling development, such as genetics and diet, are discussed, along with how the amount and type of marbling are used in USDA grading (Prime, Choice, Select) as indicators of expected eating quality. Finally, the sources emphasize the importance of using appropriate grilling techniques to manage the rendering fat effectively and unlock the full potential of marbled cuts.