Two of the most influential voices in U.S. nutrition guidance are aligned on the basics, yet they diverge on two major cooking ingredients: butter and beef tallow. As traditional cooking fats, butter and beef tallow infuse flavor into dishes and can make meals more satisfying, but they are calorie-dense. The 2025–2030 Dietary Guidelines for Americans, developed by the Departments of Health and Human Services (HHS) and Agriculture (USDA), include the two as healthy cooking options. “When cooking with or adding fats to meals, prioritize oils with essential fatty acids, such as olive oil,” the guidelines state. “Other options can include butter or beef tallow.” But when the guidelines were released in January, the American Heart Association (AHA) issued a statement urging a cautious, evidence-based approach to using butter and tallow.…