The recently released dietary guidelines for Americans have sparked debate, particularly regarding the reclassification of certain fats. In January, the U.S. Department of Agriculture and the Department of Health and Human Services listed butter, beef tallow, and olive oil as examples of healthy fats, reversing previous recommendations that prioritized plant-based fats.
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While many nutrition experts support the inclusion of olive oil, they caution against promoting saturated fats like butter and other animal fats in place of plant-based unsaturated fats. Deirdre Tobias, a nutritional epidemiologist at Brigham and Women’s Hospital and Harvard Medical School, argues that research indicates replacing saturated fats with polyunsaturated fats leads to significant reductions in the risk of heart disease and other health issues.
The 2025 Dietary Guidelines Advisory Committee issued a scientific report in December 2024 which downplayed the focus on meat and dairy. However, the final guidelines were influenced by a different group of advisers, some with ties to the livestock industry, raising concerns about the potential health implications of promoting these fats.
Nutritionists also warn that an increased focus on fats may lead to a decrease in the intake of essential nutrients from fruits, vegetables, and whole grains. Kevin Klatt, a registered dietitian at the University of Toronto, notes that dietary changes often result in substitutions that may not improve overall health.
Fats, scientifically known as fatty acids, are categorized into saturated and unsaturated fats. Saturated fats, found in foods like butter and lard, are solid at room temperature, while unsaturated fats, such as olive oil, are typically liquid. The body requires specific fatty acids that must be obtained through diet, including omega-3 and omega-6 fatty acids.
Research supports the idea that increased saturated fat intake is linked to higher levels of low-density lipoprotein (LDL), which is associated with cardiovascular disease. The current guidelines recommend limiting saturated fat to no more than 10% of daily calories, yet the advice to increase meat and full-fat dairy consumption complicates adherence to this limit.
On the other hand, seed oils like canola and soybean, which are high in polyunsaturated fats, are notably absent from the current guidelines. These oils have been associated with better health outcomes and lower LDL cholesterol levels.
Despite concerns surrounding seed oils, experts emphasize their benefits over saturated fats. They recommend incorporating fish into the diet for healthy fats, emphasizing that not all fats are created equal, and that both omega-3 and omega-6 fatty acids are essential for health.